# phpman > man > SCREEN(1) [SCREEN(1)](https://www.chedong.com/phpMan.php/man/SCREEN/1/markdown) General Commands Manual [SCREEN(1)](https://www.chedong.com/phpMan.php/man/SCREEN/1/markdown) ## NAME screen - screen manager with VT100/ANSI terminal emulation ## SYNOPSIS **screen** [ **-**_options_ ] [ _cmd_ [ _args_ ] ] **screen** **-r** [[_pid_**.**]_tty_[**.**_host_]] **screen** **-r** _sessionowner_**/**[[_pid_**.**]_tty_[**.**_host_]] ## DESCRIPTION _Screen_ is a full-screen window manager that multiplexes a physical terminal between several processes (typically interactive shells). Each virtual terminal provides the functions of a DEC VT100 terminal and, in addition, several control functions from the ISO 6429 (ECMA 48, ANSI X3.64) and ISO 2022 standards (e.g. insert/delete line and support for multiple charac‐ ter sets). There is a scrollback history buffer for each virtual terminal and a copy-and- paste mechanism that allows moving text regions between windows. When _screen_ is called, it creates a single window with a shell in it (or the specified com‐ mand) and then gets out of your way so that you can use the program as you normally would. Then, at any time, you can create new (full-screen) windows with other programs in them (in‐ cluding more shells), kill existing windows, view a list of windows, turn output logging on and off, copy-and-paste text between windows, view the scrollback history, switch between windows in whatever manner you wish, etc. All windows run their programs completely indepen‐ dent of each other. Programs continue to run when their window is currently not visible and even when the whole _screen_ session is detached from the user's terminal. When a program ter‐ minates, _screen_ (per default) kills the window that contained it. If this window was in the foreground, the display switches to the previous window; if none are left, _screen_ exits. Shells usually distinguish between running as login-shell or sub-shell. Screen runs them as sub-shells, unless told otherwise (See shell .screenrc command). Everything you type is sent to the program running in the current window. The only exception to this is the one keystroke that is used to initiate a command to the window manager. By default, each command begins with a control-a (abbreviated C-a from now on), and is followed by one other keystroke. The command character and all the key bindings can be fully custom‐ ized to be anything you like, though they are always two characters in length. _Screen_ does not understand the prefix C- to mean control, although this notation is used in this manual for readability. Please use the caret notation (^A instead of C-a) as arguments to e.g. the _escape_ command or the _-e_ option. _Screen_ will also print out control characters in caret notation. The standard way to create a new window is to type **C-a** **c**. This creates a new window running a shell and switches to that window immediately, regardless of the state of the process run‐ ning in the current window. Similarly, you can create a new window with a custom command in it by first binding the command to a keystroke (in your .screenrc file or at the **C-a** **:** com‐ mand line) and then using it just like the **C-a** **c** command. In addition, new windows can be created by running a command like: screen emacs prog.c from a shell prompt within a previously created window. This will not run another copy of _screen_, but will instead supply the command name and its arguments to the window manager (specified in the $STY environment variable) who will use it to create the new window. The above example would start the emacs editor (editing prog.c) and switch to its window. - Note that you cannot transport environment variables from the invoking shell to the application (emacs in this case), because it is forked from the parent screen process, not from the in‐ voking shell. If /run/utmp is writable by _screen_, an appropriate record will be written to this file for each window, and removed when the window is terminated. This is useful for working with talk, script, shutdown, rsend, sccs and other similar programs that use the utmp file to de‐ termine who you are. As long as _screen_ is active on your terminal, the terminal's own record is removed from the utmp file. See also C-a L. ## GETTING STARTED Before you begin to use _screen_ you'll need to make sure you have correctly selected your ter‐ minal type, just as you would for any other termcap/terminfo program. (You can do this by using _test_ for example.) If you're impatient and want to get started without doing a lot more reading, you should re‐ member this one command: **C-a** **?**. Typing these two characters will display a list of the available _screen_ commands and their bindings. Each keystroke is discussed in the section DE‐ FAULT KEY BINDINGS. The manual section CUSTOMIZATION deals with the contents of your .screenrc. If your terminal is a true auto-margin terminal (it doesn't allow the last position on the screen to be updated without scrolling the screen) consider using a version of your termi‐ nal's termcap that has automatic margins turned _off_. This will ensure an accurate and optimal update of the screen in all circumstances. Most terminals nowadays have magic margins (auto‐ matic margins plus usable last column). This is the VT100 style type and perfectly suited for _screen_. If all you've got is a true auto-margin terminal _screen_ will be content to use it, but updating a character put into the last position on the screen may not be possible until the screen scrolls or the character is moved into a safe position in some other way. This de‐ lay can be shortened by using a terminal with insert-character capability. ## COMMAND-LINE OPTIONS Screen has the following command-line options: ### -a _screen_ must redraw parts of the display in order to implement a function. ### -A tries to restore its old window sizes when attaching to resizable terminals (those with WS in its description, e.g. suncmd or some xterm). ### -c override the default configuration file from $HOME/.screenrc to _file_. ### -d -D does not start _screen_, but detaches the elsewhere running _screen_ session. It has the same effect as typing C-a d from _screen_'s controlling terminal. **-D** is the equivalent to the power detach key. If no session can be detached, this option is ignored. In combi‐ nation with the **-r**/**-R** option more powerful effects can be achieved: ### -d -r ### -d -R ### -d -RR more than one session is available. ### -D -r ### -D -R necessary detach and logout remotely first. If it was not running create it and no‐ tify the user. This is the author's favorite. ### -D -RR Note: It is always a good idea to check the status of your sessions by means of screen -list. ### -e specifies the command character to be _x_ and the character generating a literal command character to _y_ (when typed after the command character). The default is C-a and `a', which can be specified as -e^Aa. When creating a _screen_ session, this option sets the default command character. In a multiuser session all users added will start off with this command character. But when attaching to an already running session, this option changes only the command character of the attaching user. This option is equivalent to either the commands defescape or escape respectively. ### -f -fn -fa turns flow-control on, off, or automatic switching mode. This can also be defined through the defflow .screenrc command. ### -h Specifies the history scrollback buffer to be _num_ lines high. ### -i flow-control is on. See the defflow .screenrc command for details. The use of this op‐ tion is discouraged. ### -l -ln turns login mode on or off (for /run/utmp updating). This can also be defined through the deflogin .screenrc command. ### -ls ### -list does not start _screen_, but prints a list of _pid.tty.host_ strings and creation timestamps identifying your _screen_ sessions. Sessions marked `detached' can be resumed with screen -r. Those marked `attached' are running and have a controlling terminal. If the session runs in multiuser mode, it is marked `multi'. Sessions marked as `unreachable' either live on a different host or are `dead'. An unreachable session is considered dead, when its name matches either the name of the local host, or the specified parameter, if any. See the **-r** flag for a description how to construct matches. Sessions marked as `dead' should be thoroughly checked and removed. Ask your system administrator if you are not sure. Remove sessions with the **-wipe** option. ### -L ### -Logfile By default logfile name is screenlog.0. You can set new logfile name with the -Logfile option. ### -m session is enforced, regardless whether _screen_ is called from within another _screen_ ses‐ sion or not. This flag has a special meaning in connection with the `-d' option: ### -d -m This is useful for system startup scripts. ### -D -m exits if the session terminates. ### -O affects auto-margin terminals without `LP'). This can also be set in your .screenrc by specifying `OP' in a termcap command. ### -p Preselect a window. This is useful when you want to reattach to a specific window or you want to send a command via the -X option to a specific window. As with screen's select command, - selects the blank window. As a special case for reattach, = brings up the windowlist on the blank window, while a + will create a new window. The command will not be executed if the specified window could not be found. ### -q lows: 9 indicates a directory without sessions. 10 indicates a directory with running but not attachable sessions. 11 (or more) indicates 1 (or more) usable sessions. In combination with -r the exit value is as follows: 10 indicates that there is no session to resume. 12 (or more) indicates that there are 2 (or more) sessions to resume and you should specify which one to choose. In all other cases -q has no effect. ### -Q windows. The commands will send the response to the stdout of the querying process. If there was an error in the command, then the querying process will exit with a non-zero status. The commands that can be queried now are: **echo** **info** **lastmsg** **number** **select** **time** **title** **windows** ### -r ### -r resumes a detached _screen_ session. No other options (except combinations with **-d**/**-D**) may be specified, though an optional prefix of [_pid._]_tty.host_ may be needed to distin‐ guish between multiple detached _screen_ sessions. The second form is used to connect to another user's screen session which runs in multiuser mode. This indicates that screen should look for sessions in another user's directory. This requires setuid-root. ### -R _screen_ is detached. Otherwise lists available sessions. **-RR** attempts to resume the youngest (in terms of creation time) detached _screen_ session it finds. If successful, all other command-line options are ignored. If no detached session exists, starts a new session using the specified options, just as if **-R** had not been specified. The option is set by default if _screen_ is run as a login-shell (actually screen uses -xRR in that case). For combinations with the **-d**/**-D** option see there. **Note:** Time-based session se‐ lection is a Debian addition. ### -s sets the default shell to the program specified, instead of the value in the environment variable $SHELL (or /bin/sh if not defined). This can also be defined through the shell .screenrc command. See also there. ### -S When creating a new session, this option can be used to specify a meaningful name for the session. This name identifies the session for screen -list and screen -r actions. It substitutes the default [_tty.host_] suffix. This name should not be longer then 80 sym‐ bols. ### -t sets the title (a.k.a.) for the default shell or specified program. See also the shelltitle .screenrc command. ### -T Set the $TERM environment variable using the specified term as opposed to the default setting of **screen**. ### -U stands UTF-8 encoded characters. It also sets the default encoding for new windows to `utf8'. ### -v ### -wipe does the same as screen -ls, but removes destroyed sessions instead of marking them as `dead'. An unreachable session is considered dead, when its name matches either the name of the local host, or the explicitly given parameter, if any. See the **-r** flag for a description how to construct matches. ### -x from within itself. But when cascading multiple screens, loops are not detected; take care. ### -X -S specify the screen session if you have several screen sessions running. You can use the **-d** or **-r** option to tell screen to look only for attached or detached screen sessions. Note that this command doesn't work if the session is password protected. ### -4 ### -6 ## DEFAULT KEY BINDINGS As mentioned, each _screen_ command consists of a C-a followed by one other character. For your convenience, all commands that are bound to lower-case letters are also bound to their control character counterparts (with the exception of C-a a; see below), thus, C-a c as well as C-a C-c can be used to create a window. See section CUSTOMIZATION for a description of the command. The following table shows the default key bindings. The trailing commas in boxes with multi‐ ple keystroke entries are separators, not part of the bindings. ─────────────────────────────────────────────────────────────── ### C-a ' (select) or number to switch to. ─────────────────────────────────────────────────────────────── **C-a** **"** (windowlist -b) Present a list of all windows for selection. ─────────────────────────────────────────────────────────────── **C-a** _digit_ (select 0-9) Switch to window number 0 - 9 ─────────────────────────────────────────────────────────────── **C-a** **-** (select -) Switch to window number 0 - 9, or to the blank win‐ dow. ─────────────────────────────────────────────────────────────── ### C-a tab (focus) the next region. See also _split,_ _remove,_ _only_. ─────────────────────────────────────────────────────────────── ### C-a C-a (other) played previously. Note that this binding de‐ faults to the command character typed twice, unless overridden. For instance, if you use the option **-e]x**, this command becomes ]]. ─────────────────────────────────────────────────────────────── ### C-a a (meta) ter (C-a) to window. See _escape_ command. ─────────────────────────────────────────────────────────────── ### C-a A (title) name for the current win‐ dow. ─────────────────────────────────────────────────────────────── ### C-a b, (break) ### C-a C-b ─────────────────────────────────────────────────────────────── **C-a** **B** (pow_break) Reopen the terminal line and send a break. ─────────────────────────────────────────────────────────────── ### C-a c, (screen) **C-a** **C-c** a shell and switch to that window. ─────────────────────────────────────────────────────────────── ### C-a C (clear) ─────────────────────────────────────────────────────────────── ### C-a d, (detach) **C-a** **C-d** terminal. ─────────────────────────────────────────────────────────────── **C-a** **D** **D** (pow_detach) Detach and logout. ─────────────────────────────────────────────────────────────── ### C-a f, (flow) **C-a** **C-f** _auto_. ─────────────────────────────────────────────────────────────── ### C-a F (fit) current region size. ─────────────────────────────────────────────────────────────── ### C-a C-g (vbell) bell mode. ─────────────────────────────────────────────────────────────── ### C-a h (hardcopy) current window to the file hardcopy._n_. ─────────────────────────────────────────────────────────────── ### C-a H (log) the current window to the file screenlog._n_. ─────────────────────────────────────────────────────────────── ### C-a i, (info) **C-a** **C-i** dow. ─────────────────────────────────────────────────────────────── ### C-a k, (kill) ### C-a C-k ─────────────────────────────────────────────────────────────── ### C-a l, (redisplay) **C-a** **C-l** window. ─────────────────────────────────────────────────────────────── ### C-a L (login) slot. Available only if _screen_ is configured to update the utmp database. ─────────────────────────────────────────────────────────────── ### C-a m, (lastmsg) **C-a** **C-m** displayed in the message line. ─────────────────────────────────────────────────────────────── ### C-a M (monitor) current window. ─────────────────────────────────────────────────────────────── ### C-a space, (next) **C-a** **n,** dow. ### C-a C-n ─────────────────────────────────────────────────────────────── ### C-a N (number) tle) of the current win‐ dow. ─────────────────────────────────────────────────────────────── ### C-a backspace, (prev) **C-a** **C-h,** window (opposite of **C-a** **C-a** **p,** **n**). ### C-a C-p ─────────────────────────────────────────────────────────────── ### C-a q, (xon) **C-a** **C-q** current window. ─────────────────────────────────────────────────────────────── ### C-a Q (only) the current one. See also _split,_ _remove,_ _fo__‐ _cus_. ─────────────────────────────────────────────────────────────── ### C-a r, (wrap) **C-a** **C-r** dow's line-wrap setting (turn the current win‐ dow's automatic margins on and off). ─────────────────────────────────────────────────────────────── ### C-a s, (xoff) **C-a** **C-s;** current window. ─────────────────────────────────────────────────────────────── ### C-a S (split) horizontally into two new ones. See also _only,_ _re__‐ _move,_ _focus_. ─────────────────────────────────────────────────────────────── ### C-a t, (time) ### C-a C-t ─────────────────────────────────────────────────────────────── ### C-a v (version) compilation date. ─────────────────────────────────────────────────────────────── ### C-a C-v (digraph) ### C-a w, (windows) ### C-a C-w ─────────────────────────────────────────────────────────────── ### C-a W (width) ─────────────────────────────────────────────────────────────── **C-a** **x** or **C-a** **C-x** (lockscreen) Lock this terminal. ─────────────────────────────────────────────────────────────── ### C-a X (remove) See also _split,_ _only,_ _fo__‐ _cus_. ─────────────────────────────────────────────────────────────── ### C-a z, (suspend) **C-a** **C-z** system must support BSD- style job-control. ─────────────────────────────────────────────────────────────── ### C-a Z (reset) nal to its power-on val‐ ues. ─────────────────────────────────────────────────────────────── ### C-a . (dumptermcap) file. ─────────────────────────────────────────────────────────────── ### C-a ? (help) ─────────────────────────────────────────────────────────────── ### C-a \ (quit) minate _screen_. ─────────────────────────────────────────────────────────────── ### C-a : (colon) ─────────────────────────────────────────────────────────────── ### C-a [, (copy) **C-a** **C-[**, mode. C-a esc ─────────────────────────────────────────────────────────────── **C-a** **C-],** (paste .) Write the contents of the **C-a** **]** paste buffer to the stdin queue of the current win‐ dow. ─────────────────────────────────────────────────────────────── **C-a** **{**, (history) Copy and paste a previous C-a } (command) line. ─────────────────────────────────────────────────────────────── ### C-a > (writebuf) file. ─────────────────────────────────────────────────────────────── ### C-a < (readbuf) file into the paste buf‐ fer. ─────────────────────────────────────────────────────────────── ### C-a = (removebuf) **C-a** **<** and **C-a** **>**. ─────────────────────────────────────────────────────────────── ### C-a , (license) from, where it went to and why you can use it. ─────────────────────────────────────────────────────────────── ### C-a ___ (silence) current window for inac‐ tivity. ─────────────────────────────────────────────────────────────── **C-a** **|** (split -v) Split the current region vertically into two new ones. ─────────────────────────────────────────────────────────────── **C-a** ***** (displays) Show a listing of all currently attached dis‐ plays. ─────────────────────────────────────────────────────────────── ## CUSTOMIZATION The socket directory defaults either to $HOME/.screen or simply to /tmp/screens or preferably to /run/screen chosen at compile-time. If _screen_ is installed setuid-root, then the adminis‐ trator should compile _screen_ with an adequate (not NFS mounted) socket directory. If _screen_ is not running setuid-root, the user can specify any mode 700 directory in the environment variable $SCREENDIR. When _screen_ is invoked, it executes initialization commands from the files /etc/screenrc and defaults that can be overridden in the following ways: for the global screenrc file _screen_ searches for the environment variable $SYSSCREENRC (this override feature may be disabled at compile-time). The user specific screenrc file is searched in $SCREENRC, then $HOME/.screenrc. The command line option **-c** takes precedence over the above user screenrc files. Commands in these files are used to set options, bind functions to keys, and to automatically establish one or more windows at the beginning of your _screen_ session. Commands are listed one per line, with empty lines being ignored. A command's arguments are separated by tabs or spaces, and may be surrounded by single or double quotes. A `#' turns the rest of the line into a comment, except in quotes. Unintelligible lines are warned about and ignored. Com‐ mands may contain references to environment variables. The syntax is the shell-like "$VAR " or "${VAR}". Note that this causes incompatibility with previous _screen_ versions, as now the '$'-character has to be protected with '\' if no variable substitution shall be performed. A string in single-quotes is also protected from variable substitution. Two configuration files are shipped as examples with your screen distribution: etc/screenrc and etc/etcscreenrc. They contain a number of useful examples for various commands. Customization can also be done 'on-line'. To enter the command mode type `C-a :'. Note that commands starting with def change default values, while others change current settings. The following commands are available: **acladd** _usernames_ [_crypted-pw_] **addacl** _usernames_ Enable users to fully access this screen session. _Usernames_ can be one user or a comma sepa‐ rated list of users. This command enables to attach to the _screen_ session and performs the equivalent of `aclchg _usernames_ +rwx "#?"'. executed. To add a user with restricted access, use the `aclchg' command below. If an optional second parameter is supplied, it should be a crypted password for the named user(s). `Addacl' is a synonym to `acladd'. Multi user mode only. **aclchg** _usernames_ _permbits_ _list_ **chacl** _usernames_ _permbits_ _list_ Change permissions for a comma separated list of users. Permission bits are represented as `r', `w' and `x'. Prefixing `+' grants the permission, `-' removes it. The third parameter is a comma separated list of commands and/or windows (specified either by number or title). The special list `#' refers to all windows, `?' to all commands. if _usernames_ consists of a sin‐ gle `*', all known users are affected. A command can be executed when the user has the `x' bit for it. The user can type input to a window when he has its `w' bit set and no other user obtains a writelock for this window. Other bits are currently ignored. To withdraw the writelock from another user in window 2: `aclchg _username_ -w+w 2'. To allow read-only access to the session: `aclchg _username_ -w "#"'. As soon as a user's name is known to _screen_ he can attach to the session and (per de‐ fault) has full permissions for all command and windows. Execution permission for the acl commands, `at' and others should also be removed or the user may be able to regain write per‐ mission. Rights of the special username **nobody** cannot be changed (see the su command). `Chacl' is a synonym to `aclchg'. Multi user mode only. **acldel** _username_ Remove a user from _screen_'s access control list. If currently attached, all the user's dis‐ plays are detached from the session. He cannot attach again. Multi user mode only. **aclgrp** _username_ [_groupname_] Creates groups of users that share common access rights. The name of the group is the user‐ name of the group leader. Each member of the group inherits the permissions that are granted to the group leader. That means, if a user fails an access check, another check is made for the group leader. A user is removed from all groups the special value none is used for _groupname_. If the second parameter is omitted all groups the user is in are listed. **aclumask** [[ _users_ ] _+bits_ | [ _users_ ] _-bits..._ ] **umask** [[ _users_ ] _+bits_ | [ _users_ ] _-bits..._ ] This specifies the access other users have to windows that will be created by the caller of the command. _Users_ may be no, one or a comma separated list of known usernames. If no users are specified, a list of all currently known users is assumed. _Bits_ is any combination of access control bits allowed defined with the aclchg command. The special username ? prede‐ fines the access that not yet known users will be granted to any window initially. The spe‐ cial username ?? predefines the access that not yet known users are granted to any command. Rights of the special username **nobody** cannot be changed (see the su command). `Umask' is a synonym to `aclumask'. **activity** _message_ When any activity occurs in a background window that is being monitored, _screen_ displays a notification in the message line. The notification message can be re-defined by means of the activity command. Each occurrence of `%' in _message_ is replaced by the number of the window in which activity has occurred, and each occurrence of `^G' is replaced by the definition for bell in your termcap (usually an audible bell). The default message is 'Activity in window %n' Note that monitoring is off for all windows by default, but can be altered by use of the mon‐ itor command (C-a M). ### allpartial [ on | off ] If set to on, only the current cursor line is refreshed on window change. This affects all windows and is useful for slow terminal lines. The previous setting of full/partial refresh for each window is restored with allpartial off. This is a global flag that immediately takes effect on all windows overriding the partial settings. It does not change the default redraw behavior of newly created windows. ### altscreen [ on | off ] If set to on, "alternate screen" support is enabled in virtual terminals, just like in xterm. Initial setting is `off'. **at** [_identifier_][**#**|*****|**%**] command **[**_args_ **...** **]** Execute a command at other displays or windows as if it had been entered there. At changes the context (the `current window' or `current display' setting) of the command. If the first parameter describes a non-unique context, the command will be executed multiple times. If the first parameter is of the form `_identifier_*' then identifier is matched against user names. The command is executed once for each display of the selected user(s). If the first parameter is of the form `_identifier_%' identifier is matched against displays. Displays are named after the ttys they attach. The prefix `/dev/' or `/dev/tty' may be omitted from the identifier. If _identifier_ has a `#' or nothing appended it is matched against window numbers and titles. Omitting an identifier in front of the `#', `*' or `%'-character selects all users, displays or windows because a prefix-match is performed. Note that on the affected display(s) a short message will describe what happened. Permission is checked for initiator of the at command, not for the owners of the affected display(s). Note that the '#' character works as a com‐ ment introducer when it is preceded by whitespace. This can be escaped by prefixing a '\'. Permission is checked for the initiator of the at command, not for the owners of the affected display(s). Caveat: When matching against windows, the command is executed at least once per window. Com‐ mands that change the internal arrangement of windows (like other) may be called again. In shared windows the command will be repeated for each attached display. Beware, when issuing toggle commands like login! Some commands (e.g. process) require that a display is associ‐ ated with the target windows. These commands may not work correctly under at looping over windows. **attrcolor** _attrib_ [_attribute/color-modifier_] This command can be used to highlight attributes by changing the color of the text. If the attribute _attrib_ is in use, the specified attribute/color modifier is also applied. If no modifier is given, the current one is deleted. See the STRING ESCAPES chapter for the syntax of the modifier. Screen understands two pseudo-attributes, i stands for high-intensity fore‐ ground color and I for high-intensity background color. Examples: attrcolor b "R" Change the color to bright red if bold text is to be printed. attrcolor u "-u b" Use blue text instead of underline. attrcolor b ".I" Use bright colors for bold text. Most terminal emulators do this already. attrcolor i "+b" Make bright colored text also bold. ### autodetach [ on | off ] Sets whether _screen_ will automatically detach upon hangup, which saves all your running pro‐ grams until they are resumed with a **screen** **-r** command. When turned off, a hangup signal will terminate _screen_ and all the processes it contains. Autodetach is on by default. ### autonuke [ on | off ] Sets whether a clear screen sequence should nuke all the output that has not been written to the terminal. See also obuflimit. **backtick** _id_ _lifespan_ _autorefresh_ _cmd_ _args..._ **backtick** _id_ Program the backtick command with the numerical id _id_. The output of such a command is used for substitution of the %` string escape. The specified _lifespan_ is the number of seconds the output is considered valid. After this time, the command is run again if a corresponding string escape is encountered. The _autorefresh_ parameter triggers an automatic refresh for caption and hardstatus strings after the specified number of seconds. Only the last line of output is used for substitution. If both the _lifespan_ and the _autorefresh_ parameters are zero, the backtick program is ex‐ pected to stay in the background and generate output once in a while. In this case, the com‐ mand is executed right away and screen stores the last line of output. If a new line gets printed screen will automatically refresh the hardstatus or the captions. The second form of the command deletes the backtick command with the numerical id _id_. ### bce [ on | off ] Change background-color-erase setting. If bce is set to on, all characters cleared by an erase/insert/scroll/clear operation will be displayed in the current background color. Other‐ wise the default background color is used. **bell**___**msg** [_message_] When a bell character is sent to a background window, _screen_ displays a notification in the message line. The notification message can be re-defined by this command. Each occurrence of `%' in _message_ is replaced by the number of the window to which a bell has been sent, and each occurrence of `^G' is replaced by the definition for bell in your termcap (usually an audible bell). The default message is 'Bell in window %n' An empty message can be supplied to the bell_msg command to suppress output of a message line (bell_msg ""). Without parameter, the current message is shown. **bind** [_class_] _key_ [_command_ [_args_]] Bind a command to a key. By default, most of the commands provided by _screen_ are bound to one or more keys as indicated in the DEFAULT KEY BINDINGS section, e.g. the command to create a new window is bound to C-c and c. The bind command can be used to redefine the key bind‐ ings and to define new bindings. The _key_ argument is either a single character, a two-char‐ acter sequence of the form ^x (meaning C-x), a backslash followed by an octal number (speci‐ fying the ASCII code of the character), or a backslash followed by a second character, such as \^ or \\. The argument can also be quoted, if you like. If no further argument is given, any previously established binding for this key is removed. The _command_ argument can be any command listed in this section. If a command class is specified via the -c option, the key is bound for the specified class. Use the command command to activate a class. Command classes can be used to create multiple command keys or multi-character bindings. Some examples: bind ' ' windows bind ^k bind k bind K kill bind ^f screen telnet foobar bind \033 screen -ln -t root -h 1000 9 su would bind the space key to the command that displays a list of windows (so that the command usually invoked by C-a C-w would also be available as C-a space). The next three lines remove the default kill binding from C-a C-k and C-a k. C-a K is then bound to the kill command. Then it binds C-f to the command create a window with a TELNET connection to foobar, and bind escape to the command that creates an non-login window with a.k.a. root in slot #9, with a superuser shell and a scrollback buffer of 1000 lines. bind -c demo1 0 select 10 bind -c demo1 1 select 11 bind -c demo1 2 select 12 bindkey "^B" command -c demo1 makes C-b 0 select window 10, C-b 1 window 11, etc. bind -c demo2 0 select 10 bind -c demo2 1 select 11 bind -c demo2 2 select 12 bind - command -c demo2 makes C-a - 0 select window 10, C-a - 1 window 11, etc. **bindkey** [**-d**] [**-m**] [**-a**] [[**-k**|**-t**] _string_ [_cmd-args_]] This command manages screen's input translation tables. Every entry in one of the tables tells screen how to react if a certain sequence of characters is encountered. There are three tables: one that should contain actions programmed by the user, one for the default actions used for terminal emulation and one for screen's copy mode to do cursor movement. See section INPUT TRANSLATION for a list of default key bindings. If the **-d** option is given, bindkey modifies the default table, **-m** changes the copy mode table and with neither option the user table is selected. The argument _string_ is the sequence of characters to which an action is bound. This can either be a fixed string or a termcap key‐ board capability name (selectable with the **-k** option). Some keys on a VT100 terminal can send a different string if application mode is turned on (e.g the cursor keys). Such keys have two entries in the translation table. You can select the application mode entry by specifying the **-a** option. The **-t** option tells screen not to do inter-character timing. One cannot turn off the timing if a termcap capability is used. _Cmd_ can be any of screen's commands with an arbitrary number of _args_. If _cmd_ is omitted the key-binding is removed from the table. Here are some examples of keyboard bindings: bindkey -d Show all of the default key bindings. The application mode entries are marked with [A]. bindkey -k k1 select 1 Make the "F1" key switch to window one. bindkey -t foo stuff barfoo Make "foo" an abbreviation of the word "barfoo". Timeout is disabled so that users can type slowly. bindkey "\024" mapdefault This key-binding makes ^T an escape character for key-bindings. If you did the above stuff barfoo binding, you can enter the word foo by typing ^Tfoo. If you want to insert a ^T you have to press the key twice (i.e., escape the escape binding). bindkey -k F1 command Make the F11 (not F1!) key an alternative screen escape (besides ^A). **break** [_duration_] Send a break signal for _duration_*0.25 seconds to this window. For non-Posix systems the time interval may be rounded up to full seconds. Most useful if a character device is attached to the window rather than a shell process (See also chapter WINDOW TYPES). The maximum duration of a break signal is limited to 15 seconds. ### blanker Activate the screen blanker. First the screen is cleared. If no blanker program is defined, the cursor is turned off, otherwise, the program is started and it's output is written to the screen. The screen blanker is killed with the first keypress, the read key is discarded. This command is normally used together with the idle command. **blankerprg** [_program-args_] Defines a blanker program. Disables the blanker program if an empty argument is given. Shows the currently set blanker program if no arguments are given. **breaktype** [_tcsendbreak_|_TIOCSBRK_|_TCSBRK_] Choose one of the available methods of generating a break signal for terminal devices. This command should affect the current window only. But it still behaves identical to defbreak‐ type. This will be changed in the future. Calling breaktype with no parameter displays the break method for the current window. **bufferfile** [_exchange-file_] Change the filename used for reading and writing with the paste buffer. If the optional ar‐ gument to the bufferfile command is omitted, the default setting (/tmp/screen-exchange) is reactivated. The following example will paste the system's password file into the _screen_ window (using the paste buffer, where a copy remains): C-a : bufferfile /etc/passwd C-a < C-a ] C-a : bufferfile ### bumpleft Swaps window with previous one on window list. ### bumpright Swaps window with next one on window list. ### c1 [ on | off ] Change c1 code processing. **C1** **on** tells screen to treat the input characters between 128 and 159 as control functions. Such an 8-bit code is normally the same as ESC followed by the corresponding 7-bit code. The default setting is to process c1 codes and can be changed with the defc1 command. Users with fonts that have usable characters in the c1 positions may want to turn this off. **caption** **[** **top** **|** **bottom** **]** **always**|**splitonly**[**string**] **caption** **string** [_string_] This command controls the display of the window captions. Normally a caption is only used if more than one window is shown on the display (split screen mode). But if the type is set to **always** screen shows a caption even if only one window is displayed. The default is **splitonly**. The second form changes the text used for the caption. You can use all escapes from the STRING ESCAPES chapter. Screen uses a default of `%3n %t'. You can mix both forms by providing a string as an additional argument. You can have the caption displayed either at the top or bottom of the window. The default is **bottom**. **charset** _set_ Change the current character set slot designation and charset mapping. The first four char‐ acter of _set_ are treated as charset designators while the fifth and sixth character must be in range '0' to '3' and set the GL/GR charset mapping. On every position a '.' may be used to indicate that the corresponding charset/mapping should not be changed (_set_ is padded to six characters internally by appending '.' chars). New windows have "BBBB02" as default charset, unless a encoding command is active. The current setting can be viewed with the info command. **chdir** [_directory_] Change the _current_ _directory_ of _screen_ to the specified directory or, if called without an argument, to your home directory (the value of the environment variable $HOME). All windows that are created by means of the screen command from within .screenrc or by means of C-a : screen ... or C-a c use this as their default directory. Without a chdir command, this would be the directory from which _screen_ was invoked. Hardcopy and log files are always written to the _window's_ default directory, _not_ the current directory of the process running in the window. You can use this command multiple times in your .screenrc to start various windows in different default directories, but the last chdir value will affect all the windows you create interactively. ### cjkwidth [ on | off ] Treat ambiguous width characters as full/half width. ### clear Clears the current window and saves its image to the scrollback buffer. ### collapse Reorders window on window list, removing number gaps between them. **colon** [_prefix_] Allows you to enter .screenrc command lines. Useful for on-the-fly modification of key bind‐ ings, specific window creation and changing settings. Note that the set keyword no longer ex‐ ists! Usually commands affect the current window rather than default settings for future win‐ dows. Change defaults with commands starting with 'def...'. If you consider this as the `Ex command mode' of _screen_, you may regard C-a esc (copy mode) as its `Vi command mode'. **command** **[** **-c** _class_"**]"** This command has the same effect as typing the screen escape character (^A). It is probably only useful for key bindings. If the -c option is given, select the specified command class. See also bind and bindkey. ### compacthist [ on | off ] This tells screen whether to suppress trailing blank lines when scrolling up text into the history buffer. ### console [ on | off ] Grabs or un-grabs the machines console output to a window. _Note_: Only the owner of /dev/con‐ sole can grab the console output. This command is only available if the machine supports the ioctl TIOCCONS. ### copy Enter copy/scrollback mode. This allows you to copy text from the current window and its his‐ tory into the paste buffer. In this mode a vi-like `full screen editor' is active: The editor's movement keys are: ──────────────────────────────────────────────────────────────── **h**, **C-h**, move the cursor left. ### left arrow ──────────────────────────────────────────────────────────────── **j**, **C-n**, move the cursor down. ### down arrow ──────────────────────────────────────────────────────────────── **k**, **C-p**, move the cursor up. ### up arrow ──────────────────────────────────────────────────────────────── **l** ('el'), move the cursor right. ### right arrow ──────────────────────────────────────────────────────────────── ### 0 (zero) ──────────────────────────────────────────────────────────────── **+** and **-** positions one line up and down. ──────────────────────────────────────────────────────────────── **H**, **M** and **L** move the cursor to the leftmost column of the top, center or bottom line of the window. ──────────────────────────────────────────────────────────────── **|** moves to the specified absolute column. ──────────────────────────────────────────────────────────────── **g** or **home** moves to the beginning of the buffer. ──────────────────────────────────────────────────────────────── **G** or **end** moves to the specified absolute line (default: end of buffer). ──────────────────────────────────────────────────────────────── **%** jumps to the specified percentage of the buffer. ──────────────────────────────────────────────────────────────── **^** or **$** move to the leftmost column, to the first or last non-whitespace character on the line. ──────────────────────────────────────────────────────────────── **w**, **b**, and **e** move the cursor word by word. ──────────────────────────────────────────────────────────────── **B**, **E** move the cursor WORD by WORD (as in vi). ──────────────────────────────────────────────────────────────── **f/F**, **t/T** move the cursor forward/backward to the next oc‐ currence of the target. (eg, '3fy' will move the cursor to the 3rd 'y' to the right.) ──────────────────────────────────────────────────────────────── **;** and **,** Repeat the last f/F/t/T command in the same/op‐ posite direction. ──────────────────────────────────────────────────────────────── **C-e** and **C-y** scroll the display up/down by one line while preserving the cursor position. ──────────────────────────────────────────────────────────────── **C-u** and **C-d** scroll the display up/down by the specified amount of lines while preserving the cursor po‐ sition. (Default: half screen-full). ──────────────────────────────────────────────────────────────── **C-b** and **C-f** scroll the display up/down a full screen. ──────────────────────────────────────────────────────────────── Note: Emacs style movement keys can be customized by a .screenrc command. (E.g. markkeys "h=^B:l=^F:$=^E") There is no simple method for a full emacs-style keymap, as this involves multi-character codes. Some keys are defined to do mark and replace operations. The copy range is specified by setting two marks. The text between these marks will be high‐ lighted. Press: **space** or **enter** to set the first or second mark respectively. If **mousetrack** is set to `on', marks can also be set using **left** **mouse** **click**. **Y** and **y** used to mark one whole line or to mark from start of line. **W** marks exactly one word. Any of these commands can be prefixed with a repeat count number by pressing digits **0**..**9** which is taken as a repeat count. Example: C-a C-[ H 10 j 5 Y will copy lines 11 to 15 into the paste buffer. The following search keys are defined: **/** _Vi_-like search forward. **?** _Vi_-like search backward. **C-a** **s** _Emacs_ style incremental search forward. **C-r** _Emacs_ style reverse i-search. **n** Find next search pattern. **N** Find previous search pattern. There are however some keys that act differently than in _vi_. _Vi_ does not allow one to yank rectangular blocks of text, but _screen_ does. Press: **c** or **C** to set the left or right margin respectively. If no repeat count is given, both default to the current cursor position. Example: Try this on a rather full text screen: C-a [ M 20 l SPACE c 10 l 5 j C SPACE. This moves one to the middle line of the screen, moves in 20 columns left, marks the begin‐ ning of the paste buffer, sets the left column, moves 5 columns down, sets the right column, and then marks the end of the paste buffer. Now try: C-a [ M 20 l SPACE 10 l 5 j SPACE and notice the difference in the amount of text copied. **J** joins lines. It toggles between 4 modes: lines separated by a newline character (012), lines glued seamless, lines separated by a single whitespace and comma separated lines. Note that you can prepend the newline character with a carriage return character, by issuing a crlf on. **v** or **V** is for all the _vi_ users with :set numbers - it toggles the left margin between column 9 and 1. Press **a** before the final space key to toggle in append mode. Thus the contents of the paste buffer will not be overwritten, but is appended to. **A** toggles in append mode and sets a (second) mark. **>** sets the (second) mark and writes the contents of the paste buffer to the screen-exchange file (/tmp/screen-exchange per default) once copy-mode is finished. This example demonstrates how to dump the whole scrollback buffer to that file: C-A [ g SPACE G $ >. **C-g** gives information about the current line and column. **x** or **o** exchanges the first mark and the current cursor position. You can use this to adjust an already placed mark. **C-l** ('el') will redraw the screen. **@** does nothing. Does not even exit copy mode. All keys not described here exit copy mode. **copy**___**reg** [_key_] No longer exists, use readreg instead. ### crlf [ on | off ] This affects the copying of text regions with the `C-a [' command. If it is set to `on', lines will be separated by the two character sequence `CR' - `LF'. Otherwise (default) only `LF' is used. When no parameter is given, the state is toggled. ### debug [ on | off ] Turns runtime debugging on or off. If _screen_ has been compiled with option -DDEBUG debugging available and is turned on per default. Note that this command only affects debugging output from the main SCREEN process correctly. Debug output from attacher processes can only be turned off once and forever. ### defc1 [ on | off ] Same as the **c1** command except that the default setting for new windows is changed. Initial setting is `on'. ### defautonuke [ on | off ] Same as the **autonuke** command except that the default setting for new displays is changed. Initial setting is `off'. Note that you can use the special `AN' terminal capability if you want to have a dependency on the terminal type. ### defbce [ on | off ] Same as the **bce** command except that the default setting for new windows is changed. Initial setting is `off'. **defbreaktype** [_tcsendbreak_|_TIOCSBRK_|_TCSBRK_] Choose one of the available methods of generating a break signal for terminal devices. The preferred methods are _tcsendbreak_ and _TIOCSBRK_. The third, _TCSBRK_, blocks the complete _screen_ session for the duration of the break, but it may be the only way to generate long breaks. _Tcsendbreak_ and _TIOCSBRK_ may or may not produce long breaks with spikes (e.g. 4 per second). This is not only system-dependent, this also differs between serial board drivers. Calling defbreaktype with no parameter displays the current setting. **defcharset** [_set_] Like the **charset** command except that the default setting for new windows is changed. Shows current default if called without argument. ### defdynamictitle [ on | off ] Set default behaviour for new windows regarding if screen should change window title when seeing proper escape sequence. See also "TITLES (naming windows)" section. **defescape** _xy_ Set the default command characters. This is equivalent to the escape except that it is useful multiuser sessions only. In a multiuser session escape changes the command character of the calling user, where defescape changes the default command characters for users that will be added later. ### defflow [ on | off | auto [ interrupt ]] Same as the **flow** command except that the default setting for new windows is changed. Initial setting is `auto'. Specifying **defflow** **auto** **interrupt** is the same as the command-line options ### -fa -i ### defgr [ on | off ] Same as the **gr** command except that the default setting for new windows is changed. Initial setting is `off'. **defhstatus** [_status_] The hardstatus line that all new windows will get is set to _status_. This command is useful to make the hardstatus of every window display the window number or title or the like. _Sta__‐ _tus_ may contain the same directives as in the window messages, but the directive escape char‐ acter is '^E' (octal 005) instead of '%'. This was done to make a misinterpretation of pro‐ gram generated hardstatus lines impossible. If the parameter _status_ is omitted, the current default string is displayed. Per default the hardstatus line of new windows is empty. **defencoding** _enc_ Same as the **encoding** command except that the default setting for new windows is changed. Ini‐ tial setting is the encoding taken from the terminal. ### deflog [ on | off ] Same as the **log** command except that the default setting for new windows is changed. Initial setting is `off'. ### deflogin [ on | off ] Same as the **login** command except that the default setting for new windows is changed. This is initialized with `on' as distributed (see config.h.in). **defmode** _mode_ The mode of each newly allocated pseudo-tty is set to _mode_. _Mode_ is an octal number. When no defmode command is given, mode 0622 is used. ### defmonitor [ on | off] Same as the **monitor** command except that the default setting for new windows is changed. Ini‐ tial setting is `off'. ### defmousetrack [ on | off ] Same as the **mousetrack** command except that the default setting for new windows is changed. Initial setting is `off'. **defnonblock** **[** **on** **|** **off** **|** _numsecs_**]** Same as the **nonblock** command except that the default setting for displays is changed. Initial setting is `off'. **defobuflimit** _limit_ Same as the **obuflimit** command except that the default setting for new displays is changed. Initial setting is 256 bytes. Note that you can use the special 'OL' terminal capability if you want to have a dependency on the terminal type. **defscrollback** _num_ Same as the **scrollback** command except that the default setting for new windows is changed. Initial setting is 100. **defshell** _command_ Synonym to the **shell** .screenrc command. See there. ### defsilence [ on | off ] Same as the **silence** command except that the default setting for new windows is changed. Ini‐ tial setting is `off'. **defslowpaste** _msec_ Same as the **slowpaste** command except that the default setting for new windows is changed. Initial setting is 0 milliseconds, meaning `off'. ### defutf8 [ on | off ] Same as the **utf8** command except that the default setting for new windows is changed. Initial setting is `on' if screen was started with -U, otherwise `off'. ### defwrap [ on | off ] Same as the **wrap** command except that the default setting for new windows is changed. Ini‐ tially line-wrap is on and can be toggled with the wrap command (C-a r) or by means of "C-a : wrap on|off". ### defwritelock [ on | off | auto ] Same as the **writelock** command except that the default setting for new windows is changed. Initially writelocks will off. **detach** [**-h**] Detach the _screen_ session (disconnect it from the terminal and put it into the background). This returns you to the shell where you invoked _screen_. A detached _screen_ can be resumed by invoking _screen_ with the **-r** option (see also section COMMAND-LINE OPTIONS). The **-h** option tells screen to immediately close the connection to the terminal (hangup). ### dinfo Show what screen thinks about your terminal. Useful if you want to know why features like color or the alternate charset don't work. ### displays Shows a tabular listing of all currently connected user front-ends (displays). This is most useful for multiuser sessions. The following keys can be used in displays list: ────────────────────────────────────────────────────────── **k**, **C-p**, or **up** Move up one line. ────────────────────────────────────────────────────────── **j**, **C-n**, or **down** Move down one line. ────────────────────────────────────────────────────────── **C-a** or **home** Move to the first line. ────────────────────────────────────────────────────────── **C-e** or **end** Move to the last line. ────────────────────────────────────────────────────────── **C-u** or **C-d** Move one half page up or down. ────────────────────────────────────────────────────────── **C-b** or **C-f** Move one full page up or down. ────────────────────────────────────────────────────────── **mouseclick** Move to the selected line. Avail‐ able when mousetrack is set to on. ────────────────────────────────────────────────────────── **space** Refresh the list ────────────────────────────────────────────────────────── **d** Detach that display ────────────────────────────────────────────────────────── **D** Power detach that display ────────────────────────────────────────────────────────── **C-g**, **enter**, or **escape** Exit the list ────────────────────────────────────────────────────────── The following is an example of what displays could look like: xterm 80x42 jnweiger@/dev/ttyp4 0(m11) &rWx facit 80x24 mlschroe@/dev/ttyhf nb 11(tcsh) rwx xterm 80x42 jnhollma@/dev/ttyp5 0(m11) &R.x (A) (B) (C) (D) (E) (F)(G) (H)(I) The legend is as follows: (A) The terminal type known by screen for this display. (B) Displays geometry as width x height. (C) Username who is logged in at the display. (D) Device name of the display or the attached device (E) Display is in blocking or nonblocking mode. The available modes are "nb", "NB", "Z<", "Z>", and "BL". (F) Number of the window (G) Name/title of window (H) Whether the window is shared (I) Window permissions. Made up of three characters. ┌────────────────────────────────────────────────────────┐ │ Window permissions indicators │ ├─────────────────┬──────────────────┬───────────────────┤ │ 1st character │ 2nd character │ 3rd character │ ├────┬────────────┼─────┬────────────┼─────┬─────────────┤ │**-** │no read │ **-** │no write │ **-** │no execute │ ├────┼────────────┼─────┼────────────┼─────┼─────────────┤ │**r** │read │ **w** │write │ **x** │execute │ ├────┼────────────┼─────┼────────────┼─────┼─────────────┤ │ │ │ **W** │own wlock │ │ │ ├────┴────────────┴─────┴────────────┴─────┴─────────────┤ │Indicators of permissions suppressed by a foreign wlock │ ├────┬────────────┬─────┬────────────┬─────┬─────────────┤ │**R** │read only │ **.** │no write │ │ │ └────┴────────────┴─────┴────────────┴─────┴─────────────┘ displays needs a region size of at least 10 characters wide and 5 characters high in order to display. **digraph** [_preset_[_unicode-value_]] This command prompts the user for a digraph sequence. The next two characters typed are looked up in a builtin table and the resulting character is inserted in the input stream. For example, if the user enters 'a"', an a-umlaut will be inserted. If the first character en‐ tered is a 0 (zero), _screen_ will treat the following characters (up to three) as an octal number instead. The optional argument _preset_ is treated as user input, thus one can create an umlaut key. For example the command "bindkey ^K digraph '"'" enables the user to generate an a-umlaut by typing CTRL-K a. When a non-zero _unicode-value_ is specified, a new digraph is created with the specified preset. The digraph is unset if a zero value is provided for the _unicode-value._ ### dumptermcap Write the termcap entry for the virtual terminal optimized for the currently active window to the file .termcap in the user's $HOME/.screen directory (or wherever _screen_ stores its sock‐ ets. See the FILES section below). This termcap entry is identical to the value of the envi‐ ronment variable $TERMCAP that is set up by _screen_ for each window. For terminfo based sys‐ tems you will need to run a converter like _captoinfo_ and then compile the entry with _tic_. ### dynamictitle [ on | off ] Change behaviour for windows regarding if screen should change window title when seeing proper escape sequence. See also "TITLES (naming windows)" section. **echo** [**-n**] _message_ The echo command may be used to annoy _screen_ users with a 'message of the day'. Typically in‐ stalled in a global /etc/screenrc. The option -n may be used to suppress the line feed. See also sleep. Echo is also useful for online checking of environment variables. **encoding** _enc_ [_enc_] Tell _screen_ how to interpret the input/output. The first argument sets the encoding of the current window. Each window can emulate a different encoding. The optional second parameter overwrites the encoding of the connected terminal. It should never be needed as screen uses the locale setting to detect the encoding. There is also a way to select a terminal encoding depending on the terminal type by using the KJ termcap entry. Supported encodings are eucJP, SJIS, eucKR, eucCN, Big5, GBK, KOI8-R, KOI8-U, CP1251, UTF-8, ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5, ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-15, jis. See also defencoding, which changes the default setting of a new window. **escape** _xy_ Set the command character to _x_ and the character generating a literal command character (by triggering the meta command) to _y_ (similar to the -e option). Each argument is either a sin‐ gle character, a two-character sequence of the form ^x (meaning C-x), a backslash followed by an octal number (specifying the ASCII code of the character), or a backslash followed by a second character, such as \^ or \\. The default is ^Aa. **eval** _command1_[_command2_ _..._] Parses and executes each argument as separate command. **exec** [[_fdpat_]_newcommand_ [_args_ _..._]] Run a unix subprocess (specified by an executable path _newcommand_ and its optional arguments) in the current window. The flow of data between newcommands stdin/stdout/stderr, the process originally started in the window (let us call it "application-process") and screen itself (window) is controlled by the file descriptor pattern fdpat. This pattern is basically a three character sequence representing stdin, stdout and stderr of newcommand. A dot (.) con‐ nects the file descriptor to _screen_. An exclamation mark (!) causes the file descriptor to be connected to the application-process. A colon (:) combines both. User input will go to newcommand unless newcommand receives the application-process' output (fdpats first character is `!' or `:') or a pipe symbol (|) is added (as a fourth character) to the end of fdpat. Invoking `exec' without arguments shows name and arguments of the currently running subpro‐ cess in this window. Only one subprocess a time can be running in each window. When a subprocess is running the `kill' command will affect it instead of the windows process. Refer to the postscript file `doc/fdpat.ps' for a confusing illustration of all 21 possible combinations. Each drawing shows the digits 2,1,0 representing the three file descriptors of newcommand. The box marked `W' is the usual pty that has the application-process on its slave side. The box marked `P' is the secondary pty that now has _screen_ at its master side. Abbreviations: Whitespace between the word `exec' and fdpat and the command can be omitted. Trailing dots and a fdpat consisting only of dots can be omitted. A simple `|' is synonymous for the pattern `!..|'; the word exec can be omitted here and can always be replaced by `!'. Examples: exec ... /bin/sh exec /bin/sh !/bin/sh Creates another shell in the same window, while the original shell is still running. Output of both shells is displayed and user input is sent to the new /bin/sh. exec !.. stty 19200 exec ! stty 19200 !!stty 19200 Set the speed of the window's tty. If your stty command operates on stdout, then add another `!'. exec !..| less |less This adds a pager to the window output. The special character `|' is needed to give the user control over the pager although it gets its input from the win‐ dow's process. This works, because _less_ listens on stderr (a behavior that _screen_ would not expect without the `|') when its stdin is not a tty. _Less_ versions newer than 177 fail miserably here; good old _pg_ still works. !:sed -n s/.*Error.*/\007/p Sends window output to both, the user and the sed command. The sed inserts an additional bell character (oct. 007) to the window output seen by _screen_. This will cause "Bell in window x" messages, whenever the string "Error" appears in the window. ### fit Change the window size to the size of the current region. This command is needed because screen doesn't adapt the window size automatically if the window is displayed more than once. ### flow [ on | off | auto] Sets the flow-control mode for this window. Without parameters it cycles the current win‐ dow's flow-control setting from "automatic" to "on" to "off". See the discussion on FLOW- CONTROL later on in this document for full details and note, that this is subject to change in future releases. Default is set by `defflow'. ### focus [ next | prev | up | down | left | right | top | bottom ] Move the input focus to the next region. This is done in a cyclic way so that the top left region is selected after the bottom right one. If no option is given it defaults to `next'. The next region to be selected is determined by how the regions are layered. Normally, the next region in the same layer would be selected. However, if that next region contains one or more layers, the first region in the highest layer is selected first. If you are at the last region of the current layer, `next' will move the focus to the next region in the lower layer (if there is a lower layer). `Prev' cycles in the opposite order. See split for more information about layers. The rest of the options (`up', `down', `left', `right', `top', and `bottom') are more indif‐ ferent to layers. The option `up' will move the focus upward to the region that is touching the upper left corner of the current region. `Down' will move downward to the region that is touching the lower left corner of the current region. The option `left' will move the focus leftward to the region that is touching the upper left corner of the current region, while `right' will move rightward to the region that is touching the upper right corner of the cur‐ rent region. Moving left from a left most region or moving right from a right most region will result in no action. The option `top' will move the focus to the very first region in the upper list corner of the screen, and `bottom' will move to the region in the bottom right corner of the screen. Moving up from a top most region or moving down from a bottom most region will result in no action. Useful bindings are (h, j, k, and l as in vi) bind h focus left bind j focus down bind k focus up bind l focus right bind t focus top bind b focus bottom Note that **k** is traditionally bound to the _kill_ command. **focusminsize** **[** **(** _width_**|max|**___ **)** **(** _height_**|max|**___ **)** **]** This forces any currently selected region to be automatically resized at least a certain _width_ and _height_. All other surrounding regions will be resized in order to accommodate. This constraint follows every time the focus command is used. The resize command can be used to increase either dimension of a region, but never below what is set with focusminsize. The underscore `_' is a synonym for **max**. Setting a _width_ and _height_ of `0 0' (zero zero) will undo any constraints and allow for manual resizing. Without any parameters, the minimum width and height is shown. ### gr [ on | off ] Turn GR charset switching on/off. Whenever screen sees an input character with the 8th bit set, it will use the charset stored in the GR slot and print the character with the 8th bit stripped. The default (see also defgr) is not to process GR switching because otherwise the ISO88591 charset would not work. **group** [_grouptitle_] Change or show the group the current window belongs to. Windows can be moved around between different groups by specifying the name of the destination group. Without specifying a group, the title of the current group is displayed. **hardcopy** [_-h_] [_file_] Writes out the currently displayed image to the file _file_, or, if no filename is specified, to _hardcopy.n_ in the default directory, where _n_ is the number of the current window. This either appends or overwrites the file if it exists. See below. If the option **-h** is speci‐ fied, dump also the contents of the scrollback buffer. **hardcopy**___**append** **[** **on** **|** **off** **]** If set to "on", _screen_ will append to the "hardcopy.n" files created by the command C-a h, otherwise these files are overwritten each time. Default is `off'. **hardcopydir** _directory_ Defines a directory where hardcopy files will be placed. If unset, hardcopys are dumped in _screen_'s current working directory. ### hardstatus [ on | off ] ### hardstatus [ always ] firstline | lastline | message | ignore [ string ] ### hardstatus string [ string ] This command configures the use and emulation of the terminal's hardstatus line. The first form toggles whether _screen_ will use the hardware status line to display messages. If the flag is set to `off', these messages are overlaid in reverse video mode at the display line. The default setting is `on'. The second form tells _screen_ what to do if the terminal doesn't have a hardstatus line (i.e. the termcap/terminfo capabilities "hs", "ts", "fs" and "ds" are not set). When first‐ line/lastline is used, _screen_ will reserve the first/last line of the display for the hard‐ status. message uses _screen's_ message mechanism and ignore tells _screen_ never to display the hardstatus. If you prepend the word always to the type (e.g., alwayslastline), _screen_ will use the type even if the terminal supports a hardstatus. The third form specifies the contents of the hardstatus line. '%h' is used as default string, i.e., the stored hardstatus of the current window (settable via ESC]0;^G or ESC_ESC\) is displayed. You can customize this to any string you like including the escapes from the STRING ESCAPES chapter. If you leave out the argument _string_, the current string is displayed. You can mix the second and third form by providing the string as additional argument. **height** [**-w**|**-d**] [_lines_ [_cols_]] Set the display height to a specified number of lines. When no argument is given it toggles between 24 and 42 lines display. You can also specify a width if you want to change both val‐ ues. The **-w** option tells screen to leave the display size unchanged and just set the window size, **-d** vice versa. **help**[_class_] Not really a online help, but displays a help _screen_ showing you all the key bindings. The first pages list all the internal commands followed by their current bindings. Subsequent pages will display the custom commands, one command per key. Press space when you're done reading each page, or return to exit early. All other characters are ignored. If the -c op‐ tion is given, display all bound commands for the specified command class. See also DEFAULT KEY BINDINGS section. ### history Usually users work with a shell that allows easy access to previous commands. For example csh has the command !! to repeat the last command executed. _Screen_ allows you to have a primitive way of re-calling the command that started ...: You just type the first letter of that command, then hit `C-a {' and _screen_ tries to find a previous line that matches with the `prompt character' to the left of the cursor. This line is pasted into this window's input queue. Thus you have a crude command history (made up by the visible window and its scroll‐ back buffer). **hstatus** _status_ Change the window's hardstatus line to the string _status_. **idle** [_timeout_[_cmd-args_]] Sets a command that is run after the specified number of seconds inactivity is reached. This command will normally be the blanker command to create a screen blanker, but it can be any screen command. If no command is specified, only the timeout is set. A timeout of zero (or the special timeout **off**) disables the timer. If no arguments are given, the current settings are displayed. ### ignorecase [ on | off ] Tell screen to ignore the case of characters in searches. Default is `off'. Without any op‐ tions, the state of ignorecase is toggled. ### info Uses the message line to display some information about the current window: the cursor posi‐ tion in the form (column,row) starting with (1,1), the terminal width and height plus the size of the scrollback buffer in lines, like in (80,24)+50, the current state of window XON/XOFF flow control is shown like this (See also section FLOW CONTROL): ┌─────────┬──────────────────────────────────────────────────────────┐ │+flow │ automatic flow control, currently on. │ ├─────────┼──────────────────────────────────────────────────────────┤ │-flow │ automatic flow control, currently off. │ ├─────────┼──────────────────────────────────────────────────────────┤ │+(+)flow │ flow control enabled. Agrees with automatic control. │ ├─────────┼──────────────────────────────────────────────────────────┤ │-(+)flow │ flow control disabled. Disagrees with automatic control. │ ├─────────┼──────────────────────────────────────────────────────────┤ │+(-)flow │ flow control enabled. Disagrees with automatic control. │ ├─────────┼──────────────────────────────────────────────────────────┤ │-(-)flow │ flow control disabled. Agrees with automatic control. │ └─────────┴──────────────────────────────────────────────────────────┘ The current line wrap setting (`+wrap' indicates enabled, `-wrap' not) is also shown. The flags `ins', `org', `app', `log', `mon' or `nored' are displayed when the window is in insert mode, origin mode, application-keypad mode, has output logging, activity monitoring or par‐ tial redraw enabled. The currently active character set (_G0_, _G1_, _G2_, or _G3_) and in square brackets the terminal character sets that are currently designated as _G0_ through _G3_ is shown. If the window is in UTF-8 mode, the string UTF-8 is shown instead. Additional modes depending on the type of the window are displayed at the end of the status line (See also chapter WINDOW TYPES). If the state machine of the terminal emulator is in a non-default state, the info line is started with a string identifying the current state. For system information use the time command. **ins**___**reg** [_key_] No longer exists, use paste instead. ### kill Kill current window. If there is an `exec' command running then it is killed. Otherwise the process (shell) run‐ ning in the window receives a HANGUP condition, the window structure is removed and _screen_ (your display) switches to another window. When the last window is destroyed, _screen_ exits. After a kill _screen_ switches to the previously displayed window. Note: _Emacs_ users should keep this command in mind, when killing a line. It is recommended not to use C-a as the _screen_ escape key or to rebind kill to C-a K. ### lastmsg Redisplay the last contents of the message/status line. Useful if you're typing when a mes‐ sage appears, because the message goes away when you press a key (unless your terminal has a hardware status line). Refer to the commands msgwait and msgminwait for fine tuning. **layout** **new** [_title_] Create a new layout. The screen will change to one whole region and be switched to the blank window. From here, you build the regions and the windows they show as you desire. The new layout will be numbered with the smallest available integer, starting with zero. You can op‐ tionally give a title to your new layout. Otherwise, it will have a default title of layout. You can always change the title later by using the command **layout** **title**. **layout** **remove** [_n|title_] Remove, or in other words, delete the specified layout. Either the number or the title can be specified. Without either specification, _screen_ will remove the current layout. Removing a layout does not affect your set windows or regions. ### layout next Switch to the next layout available ### layout prev Switch to the previous layout available **layout** **select** [_n|title_] Select the desired layout. Either the number or the title can be specified. Without either specification, _screen_ will prompt and ask which screen is desired. To see which layouts are available, use the **layout** **show** command. ### layout show List on the message line the number(s) and title(s) of the available layout(s). The current layout is flagged. **layout** **title** [_title_] Change or display the title of the current layout. A string given will be used to name the layout. Without any options, the current title and number is displayed on the message line. **layout** **number** [_n_] Change or display the number of the current layout. An integer given will be used to number the layout. Without any options, the current number and title is displayed on the message line. **layout** **attach** [_title_|**:last**] Change or display which layout to reattach back to. The default is **:last**, which tells _screen_ to reattach back to the last used layout just before detachment. By supplying a title, You can instruct _screen_ to reattach to a particular layout regardless which one was used at the time of detachment. Without any options, the layout to reattach to will be shown in the mes‐ sage line. **layout** **save** [_n|title_] Remember the current arrangement of regions. When used, _screen_ will remember the arrangement of vertically and horizontally split regions. This arrangement is restored when a _screen_ ses‐ sion is reattached or switched back from a different layout. If the session ends or the _screen_ process dies, the layout arrangements are lost. The **layout** **dump** command should help in this siutation. If a number or title is supplied, _screen_ will remember the arrangement of that particular layout. Without any options, _screen_ will remember the current layout. Saving your regions can be done automatically by using the **layout** **autosave** command. ### layout autosave [ on | off] Change or display the status of automatcally saving layouts. The default is **on**, meaning when _screen_ is detached or changed to a different layout, the arrangement of regions and windows will be remembered at the time of change and restored upon return. If autosave is set to **off**, that arrangement will only be restored to either to the last manual save, using **layout** **save**, or to when the layout was first created, to a single region with a single window. With‐ out either an **on** or **off**, the current status is displayed on the message line. **layout** **dump** [_filename_] Write to a file the order of splits made in the current layout. This is useful to recreate the order of your regions used in your current layout. Only the current layout is recorded. While the order of the regions are recorded, the sizes of those regions and which windows correspond to which regions are not. If no filename is specified, the default is _layout-dump_, saved in the directory that the _screen_ process was started in. If the file already exists, **layout** **dump** will append to that file. As an example: C-a : layout dump /home/user/.screenrc will save or append the layout to the user's _.screenrc_ file. ### license Display the disclaimer page. This is done whenever _screen_ is started without options, which should be often enough. See also the **startup**___**message** command. ### lockscreen Lock this display. Call a screenlock program (/local/bin/lck or /usr/bin/lock or a builtin if no other is available). Screen does not accept any command keys until this program termi‐ nates. Meanwhile processes in the windows may continue, as the windows are in the `detached' state. The screenlock program may be changed through the environment variable $LOCKPRG (which must be set in the shell from which _screen_ is started) and is executed with the user's uid and gid. Warning: When you leave other shells unlocked and you have no password set on _screen_, the lock is void: One could easily re-attach from an unlocked shell. This feature should rather be called `lockterminal'. ### log [ on | off ] Start/stop writing output of the current window to a file screenlog._n_ in the window's default directory, where _n_ is the number of the current window. This filename can be changed with the `logfile' command. If no parameter is given, the state of logging is toggled. The session log is appended to the previous contents of the file if it already exists. The current contents and the contents of the scrollback history are not included in the session log. Default is `off'. **logfile** _filename_ **logfile** **flush** _secs_ Defines the name the log files will get. The default is screenlog.%n. The second form changes the number of seconds _screen_ will wait before flushing the logfile buffer to the file-system. The default value is 10 seconds. ### login [ on | off ] Adds or removes the entry in the utmp database file for the current window. This controls if the window is `logged in'. When no parameter is given, the login state of the window is tog‐ gled. Additionally to that toggle, it is convenient having a `log in' and a `log out' key. E.g. `bind I login on' and `bind O login off' will map these keys to be C-a I and C-a O. The default setting (in config.h.in) should be on for a _screen_ that runs under suid-root. Use the deflogin command to change the default login state for new windows. Both commands are only present when _screen_ has been compiled with utmp support. **logtstamp** [**on**|**off**] **logtstamp** **after** [_secs_] ### logtstamp string [_string_] This command controls logfile time-stamp mechanism of _screen._ If time-stamps are turned on, _screen_ adds a string containing the current time to the logfile after two minutes of inactiv‐ ity. When output continues and more than another two minutes have passed, a second time- stamp is added to document the restart of the output. You can change this timeout with the second form of the command. The third form is used for customizing the time-stamp string (`-- %n:%t -- time-stamp -- %M/%d/%y %c:%s --\n' by default). ### mapdefault Tell _screen_ that the next input character should only be looked up in the default bindkey ta‐ ble. See also bindkey. ### mapnotnext Like mapdefault, but don't even look in the default bindkey table. _maptimeout_ [_timeout_] Set the inter-character timer for input sequence detection to a timeout of _timeout_ ms. The default timeout is 300ms. Maptimeout with no arguments shows the current setting. See also bindkey. **markkeys** _string_ This is a method of changing the keymap used for copy/history mode. The string is made up of _oldchar_=_newchar_ pairs which are separated by `:'. Example: The string B=^B:F=^F will change the keys `C-b' and `C-f' to the vi style binding (scroll up/down fill page). This happens to be the default binding for `B' and `F'. The command markkeys h=^B:l=^F:$=^E would set the mode for an emacs-style binding. If your terminal sends characters, that cause you to abort copy mode, then this command may help by binding these characters to do nothing. The no-op character is `@' and is used like this: markkeys @=L=H if you do not want to use the `H' or `L' commands any longer. As shown in this example, multiple keys can be assigned to one function in a single statement. **maxwin** _num_ Set the maximum window number screen will create. Doesn't affect already existing windows. The number can be increased only when there are no existing windows. ### meta Insert the command character (C-a) in the current window's input stream. ### monitor [ on | off ] Toggles activity monitoring of windows. When monitoring is turned on and an affected window is switched into the background, you will receive the activity notification message in the status line at the first sign of output and the window will also be marked with an `@' in the window-status display. Monitoring is initially off for all windows. ### mousetrack [ on | off ] This command determines whether _screen_ will watch for mouse clicks. When this command is en‐ abled, regions that have been split in various ways can be selected by pointing to them with a mouse and left-clicking them. Without specifying **on** or **off**, the current state is displayed. The default state is determined by the **defmousetrack** command. **msgminwait** _sec_ Defines the time _screen_ delays a new message when one message is currently displayed. The default is 1 second. **msgwait** _sec_ Defines the time a message is displayed if _screen_ is not disturbed by other activity. The de‐ fault is 5 seconds. ### multiuser [ on | off ] Switch between singleuser and multiuser mode. Standard _screen_ operation is singleuser. In multiuser mode the commands `acladd', `aclchg', `aclgrp' and `acldel' can be used to enable (and disable) other users accessing this _screen_ session. ### nethack [ on | off ] Changes the kind of error messages used by _screen_. When you are familiar with the game nethack, you may enjoy the nethack-style messages which will often blur the facts a little, but are much funnier to read. Anyway, standard messages often tend to be unclear as well. This option is only available if _screen_ was compiled with the NETHACK flag defined. The de‐ fault setting is then determined by the presence of the environment variable $NETHACKOPTIONS and the file ~/.nethackrc - if either one is present, the default is **on**. ### next Switch to the next window. This command can be used repeatedly to cycle through the list of windows. ### nonblock [ on | off | numsecs ] Tell screen how to deal with user interfaces (displays) that cease to accept output. This can happen if a user presses ^S or a TCP/modem connection gets cut but no hangup is received. If nonblock is **off** (this is the default) screen waits until the display restarts to accept the output. If nonblock is **on**, screen waits until the timeout is reached (**on** is treated as 1s). If the display still doesn't receive characters, screen will consider it blocked and stop sending characters to it. If at some time it restarts to accept characters, screen will un‐ block the display and redisplay the updated window contents. **number** [[+|-]_n_] Change the current window's number. If the given number _n_ is already used by another window, both windows exchange their numbers. If no argument is specified, the current window number (and title) is shown. Using `+' or `-' will change the window's number by the relative amount specified. **obuflimit** [_limit_] If the output buffer contains more bytes than the specified limit, no more data will be read from the windows. The default value is 256. If you have a fast display (like xterm), you can set it to some higher value. If no argument is specified, the current setting is displayed. ### only Kill all regions but the current one. ### other Switch to the window displayed previously. If this window does no longer exist, _other_ has the same effect as _next_. ### partial [ on | off ] Defines whether the display should be refreshed (as with _redisplay_) after switching to the current window. This command only affects the current window. To immediately affect all win‐ dows use the _allpartial_ command. Default is `off', of course. This default is fixed, as there is currently no _defpartial_ command. **password** [_crypted_pw_] Present a crypted password in your .screenrc file and _screen_ will ask for it, whenever some‐ one attempts to resume a detached. This is useful if you have privileged programs running under _screen_ and you want to protect your session from reattach attempts by another user mas‐ querading as your uid (i.e. any superuser.) If no crypted password is specified, _screen_ prompts twice for typing a password and places its encryption in the paste buffer. Default is `none', this disables password checking. **paste** [_registers_ [_dest_reg_]] Write the (concatenated) contents of the specified registers to the stdin queue of the cur‐ rent window. The register '.' is treated as the paste buffer. If no parameter is given the user is prompted for a single register to paste. The paste buffer can be filled with the **copy**, **history** and **readbuf** commands. Other registers can be filled with the **register**, **readreg** and **paste** commands. If **paste** is called with a second argument, the contents of the specified registers is pasted into the named destination register rather than the window. If '.' is used as the second argument, the displays paste buffer is the destination. Note, that **paste** uses a wide variety of resources: Whenever a second argument is specified no current window is needed. When the source specification only contains registers (not the paste buffer) then there need not be a current display (terminal attached), as the registers are a global re‐ source. The paste buffer exists once for every user. ### pastefont [ on | off ] Tell _screen_ to include font information in the paste buffer. The default is not to do so. This command is especially useful for multi character fonts like kanji. **pow**___**break** Reopen the window's terminal line and send a break condition. See `break'. **pow**___**detach** Power detach. Mainly the same as _detach_, but also sends a HANGUP signal to the parent process of _screen_. CAUTION: This will result in a logout, when _screen_ was started from your login-shell. **pow**___**detach**___**msg** [_message_] The _message_ specified here is output whenever a `Power detach' was performed. It may be used as a replacement for a logout message or to reset baud rate, etc. Without parameter, the current message is shown. ### prev Switch to the window with the next lower number. This command can be used repeatedly to cy‐ cle through the list of windows. **printcmd** [_cmd_] If _cmd_ is not an empty string, _screen_ will not use the terminal capabilities po/pf if it de‐ tects an ansi print sequence **ESC** **[** **5** **i**, but pipe the output into _cmd_. This should normally be a command like lpr or **printcmd** without a command displays the current setting. The ansi sequence **ESC** **\** ends printing and closes the pipe. Warning: Be careful with this command! If other user have write access to your terminal, they will be able to fire off print commands. **process** [_key_] Stuff the contents of the specified register into _screen_'s input queue. If no argument is given you are prompted for a register name. The text is parsed as if it had been typed in from the user's keyboard. This command can be used to bind multiple actions to a single key. ### quit Kill all windows and terminate _screen_. Note that on VT100-style terminals the keys C-4 and C-\ are identical. This makes the default bindings dangerous: Be careful not to type C-a C-4 when selecting window no. 4. Use the empty bind command (as in bind '^\') to remove a key binding. **readbuf** [_encoding_] [_filename_] Reads the contents of the specified file into the paste buffer. You can tell screen the en‐ coding of the file via the **-e** option. If no file is specified, the screen-exchange filename is used. See also **bufferfile** command. **readreg** [_encoding_] [_register_ [_filename_]] Does one of two things, dependent on number of arguments: with zero or one arguments it du‐ plicates the paste buffer contents into the register specified or entered at the prompt. With two arguments it reads the contents of the named file into the register, just as _readbuf_ reads the screen-exchange file into the paste buffer. You can tell screen the encoding of the file via the **-e** option. The following example will paste the system's password file into the _screen_ window (using register p, where a copy remains): C-a : readreg p /etc/passwd C-a : paste p ### redisplay Redisplay the current window. Needed to get a full redisplay when in partial redraw mode. **register** [**-e**_encoding_]_key-string_ Save the specified _string_ to the register _key_. The encoding of the string can be specified via the **-e** option. See also the paste command. ### remove Kill the current region. This is a no-op if there is only one region. ### removebuf Unlinks the screen-exchange file used by the commands **writebuf** and **readbuf**. ### rendition [ bell | monitor | silence | so ] attr [ color ] Change the way _screen_ renders the titles of windows that have monitor or bell flags set in caption or hardstatus or windowlist. See the STRING ESCAPES chapter for the syntax of the modifiers. The default for monitor is currently =b (bold, active colors), for bell =ub (underline, bold and active colors), and =u for silence. ### reset Reset the virtual terminal to its power-on values. Useful when strange settings (like scroll regions or graphics character set) are left over from an application. **resize** [**-h**|**-v**|**-b**|**-l**|**-p**] [[**+**|**-**] _n_[%] |**=**|**max**|**min**|___|**0**] Resize the current region. The space will be removed from or added to the surrounding regions depending on the order of the splits. The available options for resizing are `-h'(horizon‐ tal), `-v'(vertical), `-b'(both), `-l'(local to layer), and `-p'(perpendicular). Horizontal resizes will add or remove width to a region, vertical will add or remove height, and both will add or remove size from both dimensions. Local and perpendicular are similar to horizon‐ tal and vertical, but they take in account of how a region was split. If a region's last split was horizontal, a local resize will work like a vertical resize. If a region's last split was vertical, a local resize will work like a horizontal resize. Perpendicular resizes work in opposite of local resizes. If no option is specified, local is the default. The amount of lines to add or remove can be expressed a couple of different ways. By specify‐ ing a number _n_ by itself will resize the region by that absolute amount. You can specify a relative amount by prefixing a plus `+' or minus `-' to the amount, such as adding +_n_ lines or removing -_n_ lines. Resizing can also be expressed as an absolute or relative percentage by postfixing a percent sign `%'. Using zero `0' is a synonym for `min' and using an underscore `_' is a synonym for `max'. Some examples are: resize +N increase current region by N resize -N decrease current region by N resize N set current region to N resize 20% set current region to 20% of original size resize +20% increase current region by 20% resize -b = make all windows equally resize max maximize current region resize min minimize current region Without any arguments, _screen_ will prompt for how you would like to resize the current re‐ gion. See focusminsize if you want to restrict the minimum size a region can have. **screen** [_-opts_] [_n_] [_cmd_ [_args_]|**//group**] Establish a new window. The flow-control options (**-f**, **-fn** and **-fa**), title (a.k.a.) option (**-t**), login options (**-l** and **-ln**) , terminal type option (**-T** ), the all-capability-flag (**-a**) and scrollback option (**-h** ) may be specified with each command. The option (**-M**) turns monitoring on for this window. The option (**-L**) turns output logging on for this win‐ dow. If an optional number _n_ in the range 0..MAXWIN-1 is given, the window number _n_ is as‐ signed to the newly created window (or, if this number is already in-use, the next available number). If a command is specified after screen, this command (with the given arguments) is started in the window; otherwise, a shell is created. If **//group** is supplied, a container- type window is created in which other windows may be created inside it. Thus, if your .screenrc contains the lines # example for .screenrc: screen 1 screen -fn -t foobar -L 2 telnet foobar _screen_ creates a shell window (in window #1) and a window with a TELNET connection to the ma‐ chine foobar (with no flow-control using the title foobar in window #2) and will write a log‐ file (screenlog.2) of the telnet session. Note, that unlike previous versions of _screen_ no additional default window is created when screen commands are included in your .screenrc file. When the initialization is completed, _screen_ switches to the last window specified in your .screenrc file or, if none, opens a default window #0. Screen has built in some functionality of cu and telnet. See also chapter WINDOW TYPES. **scrollback** _num_ Set the size of the scrollback buffer for the current windows to _num_ lines. The default scrollback is 100 lines. See also the defscrollback command and use info to view the current setting. To access and use the contents in the scrollback buffer, use the copy command. **select** [_WindowID_] Switch to the window identified by _WindowID_. This can be a prefix of a window title (al‐ phanumeric window name) or a window number. The parameter is optional and if omitted, you get prompted for an identifier. When a new window is established, the first available number is assigned to this window. Thus, the first window can be activated by select 0. The number of windows is limited at compile-time by the MAXWIN configuration parameter (which defaults to 40). There are two special WindowIDs, - selects the internal blank window and . selects the current window. The latter is useful if used with screen's -X option. **sessionname** [_name_] Rename the current session. Note, that for screen -list the name shows up with the process-id prepended. If the argument name is omitted, the name of this session is displayed. Caution: The $STY environment variables will still reflect the old name in pre-existing shells. This may result in confusion. Use of this command is generally discouraged. Use the -S command- line option if you want to name a new session. The default is constructed from the tty and host names. **setenv** [_var_ [_string_]] Set the environment variable _var_ to value _string_. If only _var_ is specified, the user will be prompted to enter a value. If no parameters are specified, the user will be prompted for both variable and value. The environment is inherited by all subsequently forked shells. ### setsid [ on | off ] Normally screen uses different sessions and process groups for the windows. If setsid is turned _off_, this is not done anymore and all windows will be in the same process group as the screen backend process. This also breaks job-control, so be careful. The default is _on_, of course. This command is probably useful only in rare circumstances. **shell** _command_ Set the command to be used to create a new shell. This overrides the value of the environ‐ ment variable $SHELL. This is useful if you'd like to run a tty-enhancer which is expecting to execute the program specified in $SHELL. If the command begins with a '-' character, the shell will be started as a login-shell. Typical shells do only minimal initialization when not started as a login-shell. E.g. Bash will not read your ~/.bashrc unless it is a login- shell. **shelltitle** _title_ Set the title for all shells created during startup or by the C-A C-c command. For details about what a title is, see the discussion entitled TITLES (naming windows). ### silence [ on | off | sec ] Toggles silence monitoring of windows. When silence is turned on and an affected window is switched into the background, you will receive the silence notification message in the status line after a specified period of inactivity (silence). The default timeout can be changed with the `silencewait' command or by specifying a number of seconds instead of `on' or `off'. Silence is initially off for all windows. **silencewait** _sec_ Define the time that all windows monitored for silence should wait before displaying a mes‐ sage. Default 30 seconds. **sleep** _num_ This command will pause the execution of a .screenrc file for _num_ seconds. Keyboard activity will end the sleep. It may be used to give users a chance to read the messages output by echo. **slowpaste** _msec_ Define the speed at which text is inserted into the current window by the paste ("C-a ]") command. If the slowpaste value is nonzero text is written character by character. _screen_ will make a pause of _msec_ milliseconds after each single character write to allow the appli‐ cation to process its input. Only use slowpaste if your underlying system exposes flow con‐ trol problems while pasting large amounts of text. ### sort Sort the windows in alphabetical order of the window tiles. **source** _file_ Read and execute commands from file _file_. Source commands may be nested to a maximum recur‐ sion level of ten. If file is not an absolute path and screen is already processing a source command, the parent directory of the running source command file is used to search for the new command file before screen's current directory. Note that termcap/terminfo/termcapinfo commands only work at startup and reattach time, so they must be reached via the default screenrc files to have an effect. **sorendition** [_attr_[_color_]] This command is deprecated. See "rendition so" instead. **split**[**-v**] Split the current region into two new ones. All regions on the display are resized to make room for the new region. The blank window is displayed in the new region. The default is to create a horizontal split, putting the new regions on the top and bottom of each other. Using `-v' will create a vertical split, causing the new regions to appear side by side of each other. Use the remove or the only command to delete regions. Use focus to toggle between regions. When a region is split opposite of how it was previously split (that is, vertical then hori‐ zontal or horizontal then vertical), a new layer is created. The layer is used to group to‐ gether the regions that are split the same. Normally, as a user, you should not see nor have to worry about layers, but they will affect how some commands (focus and resize) behave. With this current implementation of screen, scrolling data will appear much slower in a ver‐ tically split region than one that is not. This should be taken into consideration if you need to use system commands such as **cat** or **tail** **-f**. **startup**___**message** **[** **on** **|** **off** **]** Select whether you want to see the copyright notice during startup. Default is `on', as you probably noticed. ### status [ top | up | down | bottom ] [ left | right ] The status window by default is in bottom-left corner. This command can move status messages to any corner of the screen. **top** is the same as **up**, **down** is the same as **bottom**. **stuff** [_string_] Stuff the string _string_ in the input buffer of the current window. This is like the paste command but with much less overhead. Without a parameter, screen will prompt for a string to stuff. You cannot paste large buffers with the stuff command. It is most useful for key bindings. See also bindkey. **su** [_username_ [_password_ [_password2_]]] Substitute the user of a display. The command prompts for all parameters that are omitted. If passwords are specified as parameters, they have to be specified un-crypted. The first pass‐ word is matched against the systems passwd database, the second password is matched against the _screen_ password as set with the commands acladd or password. Su may be useful for the _screen_ administrator to test multiuser setups. When the identification fails, the user has access to the commands available for user **nobody**. These are detach, license, version, help and displays. ### suspend Suspend _screen_. The windows are in the `detached' state, while _screen_ is suspended. This feature relies on the shell being able to do job control. **term** _term_ In each window's environment _screen_ opens, the $TERM variable is set to screen by default. But when no description for screen is installed in the local termcap or terminfo data base, you set $TERM to - say - vt100. This won't do much harm, as _screen_ is VT100/ANSI compatible. The use of the term command is discouraged for non-default purpose. That is, one may want to specify special $TERM settings (e.g. vt100) for the next screen rlogin othermachine command. Use the command screen -T vt100 rlogin othermachine rather than setting and resetting the de‐ fault. **termcap** _term_ _terminal-tweaks_[_window-tweaks]_ **terminfo** _term_ _terminal-tweaks_[_window-tweaks]_ **termcapinfo** _term_ _terminal-tweaks_[_window-tweaks]_ Use this command to modify your terminal's termcap entry without going through all the has‐ sles involved in creating a custom termcap entry. Plus, you can optionally customize the termcap generated for the windows. You have to place these commands in one of the screenrc startup files, as they are meaningless once the terminal emulator is booted. If your system uses the terminfo database rather than termcap, _screen_ will understand the `terminfo' command, which has the same effects as the `termcap' command. Two separate com‐ mands are provided, as there are subtle syntactic differences, e.g. when parameter interpola‐ tion (using `%') is required. Note that termcap names of the capabilities have to be used with the `terminfo' command. In many cases, where the arguments are valid in both terminfo and termcap syntax, you can use the command `termcapinfo', which is just a shorthand for a pair of `termcap' and `terminfo' commands with identical arguments. The first argument specifies which terminal(s) should be affected by this definition. You can specify multiple terminal names by separating them with `|'s. Use `*' to match all ter‐ minals and `vt*' to match all terminals that begin with vt. Each _tweak_ argument contains one or more termcap defines (separated by `:'s) to be inserted at the start of the appropriate termcap entry, enhancing it or overriding existing values. The first tweak modifies your terminal's termcap, and contains definitions that your terminal uses to perform certain functions. Specify a null string to leave this unchanged (e.g. ''). The second (optional) tweak modifies all the window termcaps, and should contain definitions that _screen_ understands (see the VIRTUAL TERMINAL section). Some examples: termcap xterm* LP:hs@ Informs _screen_ that all terminals that begin with `xterm' have firm auto-margins that allow the last position on the screen to be updated (LP), but they don't really have a status line (no 'hs' - append `@' to turn entries off). Note that we assume `LP' for all terminal names that start with vt, but only if you don't specify a termcap command for that terminal. termcap vt* LP termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l Specifies the firm-margined `LP' capability for all terminals that begin with `vt', and the second line will also add the escape-sequences to switch into (Z0) and back out of (Z1) 132-character-per-line mode if this is a VT102 or VT220. (You must specify Z0 and Z1 in your termcap to use the width-changing commands.) termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4 This leaves your vt100 termcap alone and adds the function key labels to each window's term‐ cap entry. termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P Takes a h19 or z19 termcap and turns off auto-margins (am@) and enables the insert mode (im) and end-insert (ei) capabilities (the `@' in the `im' string is after the `=', so it is part of the string). Having the `im' and `ei' definitions put into your terminal's termcap will cause _screen_ to automatically advertise the character-insert capability in each window's termcap. Each window will also get the delete-character capability (dc) added to its term‐ cap, which _screen_ will translate into a line-update for the terminal (we're pretending it doesn't support character deletion). If you would like to fully specify each window's termcap entry, you should instead set the $SCREENCAP variable prior to running _screen_. See the discussion on the VIRTUAL TERMINAL in this manual, and the [termcap(5)](https://www.chedong.com/phpMan.php/man/termcap/5/markdown) man page for more information on termcap definitions. **time** [_string_] Uses the message line to display the time of day, the host name, and the load averages over 1, 5, and 15 minutes (if this is available on your system). For window specific information, use info. If a string is specified, it changes the format of the time report like it is described in the STRING ESCAPES chapter. Screen uses a default of "%c:%s %M %d %H%? %l%?". **title** [_windowtitle_] Set the name of the current window to _windowtitle_. If no name is specified, _screen_ prompts for one. This command was known as `aka' in previous releases. ### unbindall Unbind all the bindings. This can be useful when screen is used solely for its detaching abilities, such as when letting a console application run as a daemon. If, for some reason, it is necessary to bind commands after this, use 'screen -X'. **unsetenv** _var_ Unset an environment variable. ### utf8 [ on | off [ on | off ]] Change the encoding used in the current window. If utf8 is enabled, the strings sent to the window will be UTF-8 encoded and vice versa. Omitting the parameter toggles the setting. If a second parameter is given, the display's encoding is also changed (this should rather be done with screen's -U option). See also defutf8, which changes the default setting of a new win‐ dow. ### vbell [ on | off ] Sets the visual bell setting for this window. Omitting the parameter toggles the setting. If vbell is switched on, but your terminal does not support a visual bell, a `vbell-message' is displayed in the status line when the bell character (^G) is received. Visual bell support of a terminal is defined by the termcap variable `vb' (terminfo: 'flash'). Per default, vbell is off, thus the audible bell is used. See also `bell_msg'. **vbell**___**msg** [_message_] Sets the visual bell message. _message_ is printed to the status line if the window receives a bell character (^G), vbell is set to on, but the terminal does not support a visual bell. The default message is Wuff, Wuff!!. Without a parameter, the current message is shown. **vbellwait** _sec_ Define a delay in seconds after each display of _screen_'s visual bell message. The default is 1 second. ### verbose [ on | off ] If verbose is switched on, the command name is echoed, whenever a window is created (or res‐ urrected from zombie state). Default is off. Without a parameter, the current setting is shown. ### version Print the current version and the compile date in the status line. **wall** _message_ Write a message to all displays. The message will appear in the terminal's status line. **width** [**-w**|**-d**] [_cols_ [_lines_]] Toggle the window width between 80 and 132 columns or set it to _cols_ columns if an argument is specified. This requires a capable terminal and the termcap entries Z0 and Z1. See the termcap command for more information. You can also specify a new height if you want to change both values. The **-w** option tells screen to leave the display size unchanged and just set the window size, **-d** vice versa. ### windowlist [ -b ] [ -m ] [ -g ] **windowlist** **string** [_string_] **windowlist** **title** [_title_] Display all windows in a table for visual window selection. If screen was in a window group, screen will back out of the group and then display the windows in that group. If the **-b** op‐ tion is given, screen will switch to the blank window before presenting the list, so that the current window is also selectable. The **-m** option changes the order of the windows, instead of sorting by window numbers screen uses its internal most-recently-used list. The **-g** option will show the windows inside any groups in that level and downwards. The following keys are used to navigate in windowlist: ───────────────────────────────────────────────────────────────────── **k**, **C-p**, or **up** Move up one line. ───────────────────────────────────────────────────────────────────── **j**, **C-n**, or **down** Move down one line. ───────────────────────────────────────────────────────────────────── **C-g** or **escape** Exit windowlist. ───────────────────────────────────────────────────────────────────── **C-a** or **home** Move to the first line. ───────────────────────────────────────────────────────────────────── **C-e** or **end** Move to the last line. ───────────────────────────────────────────────────────────────────── **C-u** or **C-d** Move one half page up or down. ───────────────────────────────────────────────────────────────────── **C-b** or **C-f** Move one full page up or down. ───────────────────────────────────────────────────────────────────── **0..9** Using the number keys, move to the selected line. ───────────────────────────────────────────────────────────────────── **mouseclick** Move to the selected line. Available when mouse‐ track is set to on ───────────────────────────────────────────────────────────────────── **/** Search. ───────────────────────────────────────────────────────────────────── **n** Repeat search in the forward direction. ───────────────────────────────────────────────────────────────────── **N** Repeat search in the backward direction. ───────────────────────────────────────────────────────────────────── **m** Toggle MRU. ───────────────────────────────────────────────────────────────────── **g** Toggle group nesting. ───────────────────────────────────────────────────────────────────── **a** All window view. ───────────────────────────────────────────────────────────────────── **C-h** or backspace Back out the group. ───────────────────────────────────────────────────────────────────── **,** Switch numbers with the previous window. ───────────────────────────────────────────────────────────────────── **.** Switch numbers with the next window. ───────────────────────────────────────────────────────────────────── **K** Kill that window. ───────────────────────────────────────────────────────────────────── **space** or **enter** Select that window. ───────────────────────────────────────────────────────────────────── The table format can be changed with the **string** and **title** option, the title is displayed as table heading, while the lines are made by using the string setting. The default setting is Num Name%=Flags for the title and %3n %t%=%f for the lines. See the STRING ESCAPES chapter for more codes (e.g. color settings). Windowlist needs a region size of at least 10 characters wide and 6 characters high in order to display. ### windows [ string ] Uses the message line to display a list of all the windows. Each window is listed by number with the name of process that has been started in the window (or its title); the current win‐ dow is marked with a `*'; the previous window is marked with a `-'; all the windows that are logged in are marked with a `$'; a background window that has received a bell is marked with a `!'; a background window that is being monitored and has had activity occur is marked with an `@'; a window which has output logging turned on is marked with `(L)'; windows occupied by other users are marked with `&'; windows in the zombie state are marked with `Z'. If this list is too long to fit on the terminal's status line only the portion around the current window is displayed. The optional string parameter follows the STRING ESCAPES format. If string parameter is passed, the output size is unlimited. The default command without any parameter is limited to a size of 1024 bytes. ### wrap [ on | off ] Sets the line-wrap setting for the current window. When line-wrap is on, the second consecu‐ tive printable character output at the last column of a line will wrap to the start of the following line. As an added feature, backspace (^H) will also wrap through the left margin to the previous line. Default is `on'. Without any options, the state of wrap is toggled. **writebuf** [**-e** _encoding_] [_filename_] Writes the contents of the paste buffer to the specified file, or the public accessible screen-exchange file if no filename is given. This is thought of as a primitive means of com‐ munication between _screen_ users on the same host. If an encoding is specified the paste buf‐ fer is recoded on the fly to match the encoding. The filename can be set with the _bufferfile_ command and defaults to /tmp/screen-exchange. ### writelock [ on | off | auto] In addition to access control lists, not all users may be able to write to the same window at once. Per default, writelock is in `auto' mode and grants exclusive input permission to the user who is the first to switch to the particular window. When he leaves the window, other users may obtain the writelock (automatically). The writelock of the current window is dis‐ abled by the command writelock off. If the user issues the command writelock on he keeps the exclusive write permission while switching to other windows. ### xoff ### xon Insert a CTRL-s / CTRL-q character to the stdin queue of the current window. ### zmodem [ off | auto | catch | pass ] **zmodem** **sendcmd** [_string_] **zmodem** **recvcmd** [_string_] Define zmodem support for screen. Screen understands two different modes when it detects a zmodem request: pass and catch. If the mode is set to pass, screen will relay all data to the attacher until the end of the transmission is reached. In catch mode screen acts as a zmodem endpoint and starts the corresponding rz/sz commands. If the mode is set to auto, screen will use catch if the window is a tty (e.g. a serial line), otherwise it will use pass. You can define the templates screen uses in catch mode via the second and the third form. Note also that this is an experimental feature. **zombie** [_keys_**[**onerror**]**] Per default _screen_ windows are removed from the window list as soon as the windows process (e.g. shell) exits. When a string of two keys is specified to the zombie command, `dead' win‐ dows will remain in the list. The **kill** command may be used to remove such a window. Pressing the first key in the dead window has the same effect. When pressing the second key, _screen_ will attempt to resurrect the window. The process that was initially running in the window will be launched again. Calling **zombie** without parameters will clear the zombie setting, thus making windows disappear when their process exits. As the zombie-setting is manipulated globally for all windows, this command should probably be called **defzombie**, but it isn't. Optionally you can put the word onerror after the keys. This will cause screen to monitor exit status of the process running in the window. If it exits normally ('0'), the window dis‐ appears. Any other exit value causes the window to become a zombie. **zombie**___**timeout**[_seconds_] Per default _screen_ windows are removed from the window list as soon as the windows process (e.g. shell) exits. If **zombie** keys are defined (compare with above **zombie** command), it is possible to also set a timeout when screen tries to automatically reconnect a dead screen window. ## THE MESSAGE LINE _Screen_ displays informational messages and other diagnostics in a _message_ _line_. While this line is distributed to appear at the bottom of the screen, it can be defined to appear at the top of the screen during compilation. If your terminal has a status line defined in its termcap, _screen_ will use this for displaying its messages, otherwise a line of the current screen will be temporarily overwritten and output will be momentarily interrupted. The mes‐ sage line is automatically removed after a few seconds delay, but it can also be removed early (on terminals without a status line) by beginning to type. The message line facility can be used by an application running in the current window by means of the ANSI _Privacy_ _message_ control sequence. For instance, from within the shell, try something like: echo '^Hello world from window '$WINDOW'\\' where '' is an _escape_, '^' is a literal up-arrow, and '\\' turns into a single back‐ slash. ## WINDOW TYPES Screen provides three different window types. New windows are created with _screen_'s **screen** command (see also the entry in chapter CUSTOMIZATION). The first parameter to the **screen** com‐ mand defines which type of window is created. The different window types are all special cases of the normal type. They have been added in order to allow _screen_ to be used effi‐ ciently as a console multiplexer with 100 or more windows. • The normal window contains a shell (default, if no parameter is given) or any other system command that could be executed from a shell (e.g. **slogin**, etc...) • If a tty (character special device) name (e.g. /dev/ttya) is specified as the first param‐ eter, then the window is directly connected to this device. This window type is similar to screen cu -l /dev/ttya. Read and write access is required on the device node, an ex‐ clusive open is attempted on the node to mark the connection line as busy. An optional parameter is allowed consisting of a comma separated list of flags in the notation used by [stty(1)](https://www.chedong.com/phpMan.php/man/stty/1/markdown): Usually 300, 1200, 9600 or 19200. This affects transmission as well as receive speed. cs8 or cs7 Specify the transmission of eight (or seven) bits per byte. ixon or -ixon Enables (or disables) software flow-control (CTRL-S/CTRL-Q) for sending data. ixoff or -ixoff Enables (or disables) software flow-control for receiving data. istrip or -istrip Clear (or keep) the eight bit in each received byte. You may want to specify as many of these options as applicable. Unspecified options cause the terminal driver to make up the parameter values of the connection. These values are system dependent and may be in defaults or values saved from a previous connection. For tty windows, the **info** command shows some of the modem control lines in the status line. These may include `RTS', `CTS', 'DTR', `DSR', `CD' and more. This depends on the available ioctl()'s and system header files as well as the on the physical capabilities of the serial board. Signals that are logical low (inactive) have their name preceded by an exclamation mark (!), otherwise the signal is logical high (active). Signals not sup‐ ported by the hardware but available to the ioctl() interface are usually shown low. When the CLOCAL status bit is true, the whole set of modem signals is placed inside curly braces ({ and }). When the CRTSCTS or TIOCSOFTCAR bit is set, the signals `CTS' or `CD' are shown in parenthesis, respectively. For tty windows, the command **break** causes the Data transmission line (TxD) to go low for a specified period of time. This is expected to be interpreted as break signal on the other side. No data is sent and no modem control line is changed when a **break** is issued. • If the first parameter is //telnet, the second parameter is expected to be a host name, and an optional third parameter may specify a TCP port number (default decimal 23). Screen will connect to a server listening on the remote host and use the telnet protocol to communicate with that server. For telnet windows, the command **info** shows details about the connection in square brackets ([ and ]) at the end of the status line. b BINARY. The connection is in binary mode. e ECHO. Local echo is disabled. c SGA. The connection is in `character mode' (default: `line mode'). t TTYPE. The terminal type has been requested by the remote host. Screen sends the name screen unless instructed otherwise (see also the command `term'). w NAWS. The remote site is notified about window size changes. f LFLOW. The remote host will send flow control information. (Ignored at the mo‐ ment.) Additional flags for debugging are x, t and n (XDISPLOC, TSPEED and NEWENV). For telnet windows, the command **break** sends the telnet code IAC BREAK (decimal 243) to the remote host. This window type is only available if _screen_ was compiled with the ENABLE_TELNET op‐ tion defined. ## STRING ESCAPES Screen provides an escape mechanism to insert information like the current time into messages or file names. The escape character is '%' with one exception: inside of a window's hardsta‐ tus '^%' ('^E') is used instead. Here is the full list of supported escapes: % the escape character itself E sets %? to true if the escape character has been pressed. e encoding f flags of the window, see windows for meanings of the various flags F sets %? to true if the window has the focus h hardstatus of the window H hostname of the system n window number P sets %? to true if the current region is in copy/paste mode S session name s window size t window title u all other users on this window w all window numbers and names. With '-' qualifier: up to the current window; with '+' qualifier: starting with the window after the current one. W all window numbers and names except the current one x the executed command including arguments running in this windows X the executed command without arguments running in this windows ? the part to the next '%?' is displayed only if a '%' escape inside the part expands to a non-empty string : else part of '%?' = pad the string to the display's width (like TeX's hfill). If a number is specified, pad to the percentage of the window's width. A '0' qualifier tells screen to treat the number as absolute position. You can specify to pad relative to the last absolute pad position by adding a '+' qualifier or to pad relative to the right margin by using '-'. The padding truncates the string if the specified position lies before the cur‐ rent position. Add the 'L' qualifier to change this. < same as '%=' but just do truncation, do not fill with spaces > mark the current text position for the next truncation. When screen needs to do trun‐ cation, it tries to do it in a way that the marked position gets moved to the speci‐ fied percentage of the output area. (The area starts from the last absolute pad posi‐ tion and ends with the position specified by the truncation operator.) The 'L' quali‐ fier tells screen to mark the truncated parts with '...'. { attribute/color modifier string terminated by the next } ` Substitute with the output of a 'backtick' command. The length qualifier is misused to identify one of the commands. The 'c' and 'C' escape may be qualified with a '0' to make _screen_ use zero instead of space as fill character. The '0' qualifier also makes the '=' escape use absolute positions. The 'n' and '=' escapes understand a length qualifier (e.g. '%3n'), 'D' and 'M' can be prefixed with 'L' to generate long names, 'w' and 'W' also show the window flags if 'L' is given. An attribute/color modifier is used to change the attributes or the color settings. Its for‐ mat is [attribute modifier] [color description]. The attribute modifier must be prefixed by a change type indicator if it can be confused with a color description. The following change types are known: + add the specified set to the current attributes - remove the set from the current attributes ! invert the set in the current attributes = change the current attributes to the specified set The attribute set can either be specified as a hexadecimal number or a combination of the following letters: d dim u underline b bold r reverse s /standout B blinking Colors are coded either as a hexadecimal number or two letters specifying the desired back‐ ground and foreground color (in that order). The following colors are known: k black r red g green y yellow b blue m magenta c cyan w white d default color . leave color unchanged The capitalized versions of the letter specify bright colors. You can also use the pseudo- color 'i' to set just the brightness and leave the color unchanged. A one digit/letter color description is treated as foreground or background color dependent on the current attributes: if reverse mode is set, the background color is changed instead of the foreground color. If you don't like this, prefix the color with a .. If you want the same behavior for two-letter color descriptions, also prefix them with a .. As a special case, %{-} restores the attributes and colors that were set before the last change was made (i.e., pops one level of the color-change stack). Examples: G set color to bright green +b r use bold red = yd clear all attributes, write in default color on yellow background. %-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%< The available windows centered at the current window and truncated to the available width. The current window is displayed white on blue. This can be used with hardsta‐ tus alwayslastline. %?%F%{.R.}%?%3n %t%? [%h]%? The window number and title and the window's hardstatus, if one is set. Also use a red background if this is the active focus. Useful for caption string. ## FLOW-CONTROL Each window has a flow-control setting that determines how _screen_ deals with the XON and XOFF characters (and perhaps the interrupt character). When flow-control is turned off, _screen_ ignores the XON and XOFF characters, which allows the user to send them to the current pro‐ gram by simply typing them (useful for the _emacs_ editor, for instance). The trade-off is that it will take longer for output from a normal program to pause in response to an XOFF. With flow-control turned on, XON and XOFF characters are used to immediately pause the output of the current window. You can still send these characters to the current program, but you must use the appropriate two-character _screen_ commands (typically C-a q (xon) and C-a s (xoff)). The xon/xoff commands are also useful for typing C-s and C-q past a terminal that intercepts these characters. Each window has an initial flow-control value set with either the **-f** option or the defflow .screenrc command. Per default the windows are set to automatic flow-switching. It can then be toggled between the three states 'fixed on', 'fixed off' and 'automatic' interactively with the flow command bound to "C-a f". The automatic flow-switching mode deals with flow control using the TIOCPKT mode (like rlogin does). If the tty driver does not support TIOCPKT, _screen_ tries to find out the right mode based on the current setting of the application keypad - when it is enabled, flow-control is turned off and visa versa. Of course, you can still manipulate flow-control manually when needed. If you're running with flow-control enabled and find that pressing the interrupt key (usually C-c) does not interrupt the display until another 6-8 lines have scrolled by, try running _screen_ with the interrupt option (add the interrupt flag to the flow command in your .screenrc, or use the **-i** command-line option). This causes the output that _screen_ has accu‐ mulated from the interrupted program to be flushed. One disadvantage is that the virtual terminal's memory contains the non-flushed version of the output, which in rare cases can cause minor inaccuracies in the output. For example, if you switch screens and return, or update the screen with C-a l you would see the version of the output you would have gotten without interrupt being on. Also, you might need to turn off flow-control (or use auto-flow mode to turn it off automatically) when running a program that expects you to type the inter‐ rupt character as input, as it is possible to interrupt the output of the virtual terminal to your physical terminal when flow-control is enabled. If this happens, a simple refresh of the screen with C-a l will restore it. Give each mode a try, and use whichever mode you find more comfortable. ### TITLES (naming windows) You can customize each window's name in the window display (viewed with the windows command (C-a w)) by setting it with one of the title commands. Normally the name displayed is the actual command name of the program created in the window. However, it is sometimes useful to distinguish various programs of the same name or to change the name on-the-fly to reflect the current state of the window. The default name for all shell windows can be set with the shelltitle command in the .screenrc file, while all other windows are created with a screen command and thus can have their name set with the **-t** option. Interactively, there is the title-string escape-sequence (k_name_\) and the title command (C-a A). The former can be output from an applica‐ tion to control the window's name under software control, and the latter will prompt for a name when typed. You can also bind pre-defined names to keys with the title command to set things quickly without prompting. Changing title by this escape sequence can be controlled by **defdynamictitle** and **dynamictitle** commands. Finally, _screen_ has a shell-specific heuristic that is enabled by setting the window's name to _search|name_ and arranging to have a null title escape-sequence output as a part of your prompt. The _search_ portion specifies an end-of-prompt search string, while the _name_ portion specifies the default shell name for the window. If the _name_ ends in a `:' _screen_ will add what it believes to be the current command running in the window to the end of the window's shell name (e.g. _name:cmd_). Otherwise the current command name supersedes the shell name while it is running. Here's how it works: you must modify your shell prompt to output a null title-escape-se‐ quence (k\) as a part of your prompt. The last part of your prompt must be the same as the string you specified for the _search_ portion of the title. Once this is set up, _screen_ will use the title-escape-sequence to clear the previous command name and get ready for the next command. Then, when a newline is received from the shell, a search is made for the end of the prompt. If found, it will grab the first word after the matched string and use it as the command name. If the command name begins with either '!', '%', or '^' _screen_ will use the first word on the following line (if found) in preference to the just-found name. This helps csh users get better command names when using job control or history recall commands. Here's some .screenrc examples: screen -t top 2 nice top Adding this line to your .screenrc would start a nice-d version of the top command in window 2 named top rather than nice. shelltitle '> |csh' screen 1 These commands would start a shell with the given shelltitle. The title specified is an auto-title that would expect the prompt and the typed command to look something like the fol‐ lowing: /usr/joe/src/dir> trn (it looks after the '> ' for the command name). The window status would show the name trn while the command was running, and revert to csh upon completion. bind R screen -t '% |root:' su Having this command in your .screenrc would bind the key sequence C-a R to the su command and give it an auto-title name of root:. For this auto-title to work, the screen could look something like this: % !em emacs file.c Here the user typed the csh history command !em which ran the previously entered emacs com‐ mand. The window status would show root:emacs during the execution of the command, and re‐ vert to simply root: at its completion. bind o title bind E title "" bind u title (unknown) The first binding doesn't have any arguments, so it would prompt you for a title when you type C-a o. The second binding would clear an auto-title's current setting (C-a E). The third binding would set the current window's title to (unknown) (C-a u). One thing to keep in mind when adding a null title-escape-sequence to your prompt is that some shells (like the csh) count all the non-control characters as part of the prompt's length. If these invisible characters aren't a multiple of 8 then backspacing over a tab will result in an incorrect display. One way to get around this is to use a prompt like this: set prompt='^[[0000m^[k^[\% ' The escape-sequence [0000m not only normalizes the character attributes, but all the ze‐ ros round the length of the invisible characters up to 8. Bash users will probably want to echo the escape sequence in the PROMPT_COMMAND: PROMPT_COMMAND='printf "\033k\033\134"' (I used \134 to output a `\' because of a bug in bash v1.04). ## THE VIRTUAL TERMINAL Each window in a _screen_ session emulates a VT100 terminal, with some extra functions added. The VT100 emulator is hard-coded, no other terminal types can be emulated. Usually _screen_ tries to emulate as much of the VT100/ANSI standard as possible. But if your terminal lacks certain capabilities, the emulation may not be complete. In these cases _screen_ has to tell the applications that some of the features are missing. This is no problem on ma‐ chines using termcap, because _screen_ can use the $TERMCAP variable to customize the standard _screen_ termcap. But if you do a rlogin on another machine or your machine supports only terminfo this method fails. Because of this, _screen_ offers a way to deal with these cases. Here is how it works: When _screen_ tries to figure out a terminal name for itself, it first looks for an entry named screen., where is the contents of your $TERM variable. If no such entry exists, _screen_ tries screen (or screen-w if the terminal is wide (132 cols or more)). If even this entry cannot be found, vt100 is used as a substitute. The idea is that if you have a terminal which doesn't support an important feature (e.g. delete char or clear to EOS) you can build a new termcap/terminfo entry for _screen_ (named screen.) in which this capability has been disabled. If this entry is installed on your machines you are able to do a rlogin and still keep the correct termcap/terminfo entry. The terminal name is put in the $TERM variable of all new windows. _Screen_ also sets the $TERMCAP variable reflecting the capabilities of the virtual terminal emulated. Notice that, however, on machines using the terminfo database this variable has no effect. Furthermore, the variable $WINDOW is set to the window number of each window. The actual set of capabilities supported by the virtual terminal depends on the capabilities supported by the physical terminal. If, for instance, the physical terminal does not support underscore mode, _screen_ does not put the `us' and `ue' capabilities into the window's $TERM‐ CAP variable, accordingly. However, a minimum number of capabilities must be supported by a terminal in order to run _screen_; namely scrolling, clear screen, and direct cursor addressing (in addition, _screen_ does not run on hardcopy terminals or on terminals that over-strike). Also, you can customize the $TERMCAP value used by _screen_ by using the termcap .screenrc com‐ mand, or by defining the variable $SCREENCAP prior to startup. When the latter is defined, its value will be copied verbatim into each window's $TERMCAP variable. This can either be the full terminal definition, or a filename where the terminal screen (and/or screen-w) is defined. Note that _screen_ honors the terminfo .screenrc command if the system uses the terminfo data‐ base rather than termcap. When the boolean `G0' capability is present in the termcap entry for the terminal on which _screen_ has been called, the terminal emulation of _screen_ supports multiple character sets. This allows an application to make use of, for instance, the VT100 graphics character set or national character sets. The following control functions from ISO 2022 are supported: _lock_ _shift_ _G0_ (_SI_), _lock_ _shift_ _G1_ (_SO_), _lock_ _shift_ _G2_, _lock_ _shift_ _G3_, _single_ _shift_ _G2_, and _single_ _shift_ _G3_. When a virtual terminal is created or reset, the ASCII character set is designated as _G0_ through _G3_. When the `G0' capability is present, _screen_ evaluates the capabilities `S0', `E0', and `C0' if present. `S0' is the sequence the terminal uses to enable and start the graphics character set rather than _SI_. `E0' is the corresponding replacement for _SO_. `C0' gives a character by character translation string that is used during semi-graphics mode. This string is built like the `acsc' terminfo capability. When the `po' and `pf' capabilities are present in the terminal's termcap entry, applications running in a _screen_ window can send output to the printer port of the terminal. This allows a user to have an application in one window sending output to a printer connected to the ter‐ minal, while all other windows are still active (the printer port is enabled and disabled again for each chunk of output). As a side-effect, programs running in different windows can send output to the printer simultaneously. Data sent to the printer is not displayed in the window. The _info_ command displays a line starting `PRIN' while the printer is active. _Screen_ maintains a hardstatus line for every window. If a window gets selected, the display's hardstatus will be updated to match the window's hardstatus line. If the display has no hard‐ status the line will be displayed as a standard _screen_ message. The hardstatus line can be changed with the ANSI Application Program Command (APC): ESC_ESC\. As a convenience for xterm users the sequence ESC]0..2;^G is also accepted. Some capabilities are only put into the $TERMCAP variable of the virtual terminal if they can be efficiently implemented by the physical terminal. For instance, `dl' (delete line) is only put into the $TERMCAP variable if the terminal supports either delete line itself or scrolling regions. Note that this may provoke confusion, when the session is reattached on a different terminal, as the value of $TERMCAP cannot be modified by parent processes. The "alternate screen" capability is not enabled by default. Set the **altscreen** .screenrc command to enable it. The following is a list of control sequences recognized by _screen_. (V) and (A) indicate VT100-specific and ANSI- or ISO-specific functions, respectively. **ESC** **E** Next Line **ESC** **D** Index **ESC** **M** Reverse Index **ESC** **H** Horizontal Tab Set **ESC** **Z** Send VT100 Identification String **ESC** **7** (V) Save Cursor and Attributes **ESC** **8** (V) Restore Cursor and Attributes **ESC** **[s** (A) Save Cursor and Attributes **ESC** **[u** (A) Restore Cursor and Attributes **ESC** **c** Reset to Initial State **ESC** **g** Visual Bell **ESC** Pn **p** Cursor Visibility (97801) Pn = **6** Invisible Pn = **7** Visible **ESC** **=** (V) Application Keypad Mode **ESC** **>** (V) Numeric Keypad Mode **ESC** **#** **8** (V) Fill Screen with E's **ESC** **\** (A) String Terminator **ESC** **^** (A) Privacy Message String (Message Line) **ESC** **!** Global Message String (Message Line) **ESC** **k** A.k.a. Definition String **ESC** **P** (A) Device Control String. Outputs a string directly to the host ter‐ minal without interpretation. **ESC** ___ (A) Application Program Command (Hardstatus) **ESC** **]** **0** **;** **string** **^G** (A) Operating System Command (Hardstatus, xterm title hack) **ESC** **]** **83** **;** **cmd** **^G** (A) Execute screen command. This only works if multi-user support is compiled into screen. The pseudo-user :window: is used to check the access control list. Use addacl :window: -rwx #? to create a user with no rights and allow only the needed commands. **Control-N** (A) Lock Shift G1 (SO) **Control-O** (A) Lock Shift G0 (SI) **ESC** **n** (A) Lock Shift G2 **ESC** **o** (A) Lock Shift G3 **ESC** **N** (A) Single Shift G2 **ESC** **O** (A) Single Shift G3 **ESC** **(** Pcs (A) Designate character set as G0 **ESC** **)** Pcs (A) Designate character set as G1 **ESC** ***** Pcs (A) Designate character set as G2 **ESC** **+** Pcs (A) Designate character set as G3 **ESC** **[** Pn **;** Pn **H** Direct Cursor Addressing **ESC** **[** Pn **;** Pn **f** same as above **ESC** **[** Pn **J** Erase in Display Pn = None or **0** From Cursor to End of Screen Pn = **1** From Beginning of Screen to Cursor Pn = **2** Entire Screen **ESC** **[** Pn **K** Erase in Line Pn = None or **0** From Cursor to End of Line Pn = **1** From Beginning of Line to Cursor Pn = **2** Entire Line **ESC** **[** Pn **X** Erase character **ESC** **[** Pn **A** Cursor Up **ESC** **[** Pn **B** Cursor Down **ESC** **[** Pn **C** Cursor Right **ESC** **[** Pn **D** Cursor Left **ESC** **[** Pn **E** Cursor next line **ESC** **[** Pn **F** Cursor previous line **ESC** **[** Pn **G** Cursor horizontal position **ESC** **[** Pn **`** same as above **ESC** **[** Pn **d** Cursor vertical position **ESC** **[** Ps **;**...**;** Ps **m** Select Graphic Rendition Ps = None or **0** Default Rendition Ps = **1** Bold Ps = **2** (A) Faint Ps = **3** (A) _Standout_ Mode (ANSI: Italicized) Ps = **4** Underlined Ps = **5** Blinking Ps = **7** Negative Image Ps = **22** (A) Normal Intensity Ps = **23** (A) _Standout_ Mode off (ANSI: Italicized off) Ps = **24** (A) Not Underlined Ps = **25** (A) Not Blinking Ps = **27** (A) Positive Image Ps = **30** (A) Foreground Black Ps = **31** (A) Foreground Red Ps = **32** (A) Foreground Green Ps = **33** (A) Foreground Yellow Ps = **34** (A) Foreground Blue Ps = **35** (A) Foreground Magenta Ps = **36** (A) Foreground Cyan Ps = **37** (A) Foreground White Ps = **39** (A) Foreground Default Ps = **40** (A) Background Black Ps = **...** Ps = **49** (A) Background Default **ESC** **[** Pn **g** Tab Clear Pn = None or **0** Clear Tab at Current Position Pn = **3** Clear All Tabs **ESC** **[** Pn **;** Pn **r** (V) Set Scrolling Region **ESC** **[** Pn **I** (A) Horizontal Tab **ESC** **[** Pn **Z** (A) Backward Tab **ESC** **[** Pn **L** (A) Insert Line **ESC** **[** Pn **M** (A) Delete Line **ESC** **[** Pn **@** (A) Insert Character **ESC** **[** Pn **P** (A) Delete Character **ESC** **[** Pn **S** Scroll Scrolling Region Up **ESC** **[** Pn **T** Scroll Scrolling Region Down **ESC** **[** Pn **^** same as above **ESC** **[** Ps **;**...**;** Ps **h** Set Mode **ESC** **[** Ps **;**...**;** Ps **l** Reset Mode Ps = **4** (A) Insert Mode Ps = **20** (A) _Automatic_ _Linefeed_ Mode Ps = **34** Normal Cursor Visibility Ps = **?1** (V) Application Cursor Keys Ps = **?3** (V) Change Terminal Width to 132 columns Ps = **?5** (V) Reverse Video Ps = **?6** (V) _Origin_ Mode Ps = **?7** (V) _Wrap_ Mode Ps = **?9** X10 mouse tracking Ps = **?25** (V) Visible Cursor Ps = **?47** Alternate Screen (old xterm code) Ps = **?1000** (V) VT200 mouse tracking Ps = **?1047** Alternate Screen (new xterm code) Ps = **?1049** Alternate Screen (new xterm code) **ESC** **[** **5** **i** (A) Start relay to printer (ANSI Media Copy) **ESC** **[** **4** **i** (A) Stop relay to printer (ANSI Media Copy) **ESC** **[** **8** **;** Ph **;** Pw **t** Resize the window to `Ph' lines and `Pw' columns (SunView special) **ESC** **[** **c** Send VT100 Identification String **ESC** **[** **x** Send Terminal Parameter Report **ESC** **[** **>** **c** Send VT220 Secondary Device Attributes String **ESC** **[** **6** **n** Send Cursor Position Report ## INPUT TRANSLATION In order to do a full VT100 emulation _screen_ has to detect that a sequence of characters in the input stream was generated by a keypress on the user's keyboard and insert the VT100 style escape sequence. _Screen_ has a very flexible way of doing this by making it possible to map arbitrary commands on arbitrary sequences of characters. For standard VT100 emulation the command will always insert a string in the input buffer of the window (see also command **stuff** in the command table). Because the sequences generated by a keypress can change after a reattach from a different terminal type, it is possible to bind commands to the termcap name of the keys. _Screen_ will insert the correct binding after each reattach. See the **bindkey** command for further details on the syntax and examples. Here is the table of the default key bindings. The fourth is what command is executed if the keyboard is switched into application mode. ┌────────────────┬──────────────┬──────────┬──────────┐ │Key name │ Termcap name │ Command │ App mode │ ├────────────────┼──────────────┼──────────┼──────────┤ │Cursor up │ ku │ \033[A │ \033OA │ ├────────────────┼──────────────┼──────────┼──────────┤ │Cursor down │ kd │ \033[B │ \033OB │ ├────────────────┼──────────────┼──────────┼──────────┤ │Cursor right │ kr │ \033[C │ \033OC │ ├────────────────┼──────────────┼──────────┼──────────┤ │Cursor left │ kl │ \033[D │ \033OD │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 0 │ k0 │ \033[10~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 1 │ k1 │ \033OP │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 2 │ k2 │ \033OQ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 3 │ k3 │ \033OR │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 4 │ k4 │ \033OS │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 5 │ k5 │ \033[15~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 6 │ k6 │ \033[17~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 7 │ k7 │ \033[18~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 8 │ k8 │ \033[19~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 9 │ k9 │ \033[20~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 10 │ k; │ \033[21~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 11 │ F1 │ \033[23~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Function key 12 │ F2 │ \033[24~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Home │ kh │ \033[1~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │End │ kH │ \033[4~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Insert │ kI │ \033[2~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Delete │ kD │ \033[3~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Page up │ kP │ \033[5~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Page down │ kN │ \033[6~ │ │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 0 │ f0 │ 0 │ \033Op │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 1 │ f1 │ 1 │ \033Oq │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 2 │ f2 │ 2 │ \033Or │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 3 │ f3 │ 3 │ \033Os │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 4 │ f4 │ 4 │ \033Ot │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 5 │ f5 │ 5 │ \033Ou │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 6 │ f6 │ 6 │ \033Ov │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 7 │ f7 │ 7 │ \033Ow │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 8 │ f8 │ 8 │ \033Ox │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad 9 │ f9 │ 9 │ \033Oy │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad + │ f+ │ + │ \033Ok │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad - │ f- │ - │ \033Om │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad * │ f* │ * │ \033Oj │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad / │ f/ │ / │ \033Oo │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad = │ fq │ = │ \033OX │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad . │ f. │ . │ \033On │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad , │ f, │ , │ \033Ol │ ├────────────────┼──────────────┼──────────┼──────────┤ │Keypad enter │ fe │ \015 │ \033OM │ └────────────────┴──────────────┴──────────┴──────────┘ ## SPECIAL TERMINAL CAPABILITIES The following table describes all terminal capabilities that are recognized by _screen_ and are not in the [termcap(5)](https://www.chedong.com/phpMan.php/man/termcap/5/markdown) manual. You can place these capabilities in your termcap entries (in `/etc/termcap') or use them with the commands `termcap', `terminfo' and `termcapinfo' in your screenrc files. It is often not possible to place these capabilities in the terminfo data‐ base. ### LP _(bool) obsolete because _screen_ uses the standard 'xn' instead. ### Z0 _(str) ### Z1 _(str) ### WS _(str) _SunView(tm)_ example: '\E[8;%d;%dt'. ### NF _(bool) Same as 'flow off'. The opposite of this capability is 'nx'. ### G0 _(bool) ### S0 _(str) ### E0 _(str) ### C0 _(str) more details. ### CS _(str) ### CE _(str) ### AN _(bool) ### OL [_(num)](https://www.chedong.com/phpMan.php/man//num/markdown) ### KJ _(str) ings. ### AF _(str) almost always be set to '\E[3%dm' ('\E[3%p1%dm' on terminfo machines). ### AB _(str) ### AX _(bool) ### XC _(str) More details follow in the next section. ### XT _(bool) ### C8 _(bool) ### TF _(bool) ## CHARACTER TRANSLATION _Screen_ has a powerful mechanism to translate characters to arbitrary strings depending on the current font and terminal type. Use this feature if you want to work with a common standard character set (say ISO8851-latin1) even on terminals that scatter the more unusual characters over several national language font pages. Syntax: **XC=**__{**,,**__} __ := _