{ "mode": "man", "parameter": "visudo", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/visudo/8/json", "generated": "2026-11-08T01:23:23Z", "synopsis": "visudo [-chIOPqsV] [[-f] sudoers]", "sections": { "NAME": { "content": "visudo — edit the sudoers file\n", "subsections": [] }, "SYNOPSIS": { "content": "visudo [-chIOPqsV] [[-f] sudoers]\n", "subsections": [] }, "DESCRIPTION": { "content": "visudo edits the sudoers file in a safe fashion, analogous to vipw(8). visudo locks the\nsudoers file against multiple simultaneous edits, performs basic validity checks, and checks\nfor syntax errors before installing the edited file. If the sudoers file is currently being\nedited you will receive a message to try again later.\n\nIf the sudoers file does not exist, it will be created unless the editor exits without writ‐\ning to the file.\n\nvisudo parses the sudoers file after editing and will not save the changes if there is a syn‐\ntax error. Upon finding an error, visudo will print a message stating the line number(s)\nwhere the error occurred and the user will receive the “What now?” prompt. At this point the\nuser may enter ‘e’ to re-edit the sudoers file, ‘x’ to exit without saving the changes, or\n‘Q’ to quit and save changes. The ‘Q’ option should be used with extreme caution because if\nvisudo believes there to be a syntax error, so will sudo. If ‘e’ is typed to edit the\nsudoers file after a syntax error has been detected, the cursor will be placed on the line\nwhere the error occurred (if the editor supports this feature).\n\nThere are two sudoers settings that determine which editor visudo will run.\n\neditor A colon (‘:’) separated list of editors allowed to be used with visudo. visudo\nwill choose the editor that matches the user's SUDOEDITOR, VISUAL, or EDITOR en‐\nvironment variable if possible, or the first editor in the list that exists and\nis executable. sudo does not preserve the SUDOEDITOR, VISUAL, or EDITOR envi‐\nronment variables unless they are present in the envkeep list or the envreset\noption is disabled in the sudoers file. The default editor path is\n/usr/bin/editor which can be set at compile time via the --with-editor configure\noption.\n\nenveditor If set, visudo will use the value of the SUDOEDITOR, VISUAL, or EDITOR environ‐\nment variables before falling back on the default editor list. visudo is typi‐\ncally run as root so this option may allow a user with visudo privileges to run\narbitrary commands as root without logging. An alternative is to place a colon-\nseparated list of “safe” editors in the editor variable. visudo will then only\nuse SUDOEDITOR, VISUAL, or EDITOR if they match a value specified in editor. If\nthe envreset flag is enabled, the SUDOEDITOR, VISUAL, and/or EDITOR environment\nvariables must be present in the envkeep list for the enveditor flag to func‐\ntion when visudo is invoked via sudo. The default value is on, which can be set\nat compile time via the --with-env-editor configure option.\n\nThe options are as follows:\n", "subsections": [ { "name": "-c --check", "content": "Enable check-only mode. The existing sudoers file (and any other files it includes)\nwill be checked for syntax errors. If the path to the sudoers file was not speci‐\nfied, visudo will also check the file ownership and permissions (see the -O and -P\noptions). A message will be printed to the standard output describing the status of\nsudoers unless the -q option was specified. If the check completes successfully,\nvisudo will exit with a value of 0. If an error is encountered, visudo will exit\nwith a value of 1.\n", "flag": "-c", "long": "--check" }, { "name": "-f _ --file", "content": "Specify an alternate sudoers file location, see below. As of version 1.8.27, the\nsudoers path can be specified without using the -f option.\n", "flag": "-f", "long": "--file" }, { "name": "-h --help", "content": "Display a short help message to the standard output and exit.\n", "flag": "-h", "long": "--help" }, { "name": "-I --no-includes", "content": "Disable the editing of include files unless there is a pre-existing syntax error. By\ndefault, visudo will edit the main sudoers file and any files included via @include\nor #include directives. Files included via @includedir or #includedir are never\nedited unless they contain a syntax error.\n", "flag": "-I", "long": "--no-includes" }, { "name": "-O --owner", "content": "Enforce the default ownership (user and group) of the sudoers file. In edit mode,\nthe owner of the edited file will be set to the default. In check mode (-c), an er‐\nror will be reported if the owner is incorrect. This option is enabled by default if\nthe sudoers file was not specified.\n", "flag": "-O", "long": "--owner" }, { "name": "-P --perms", "content": "Enforce the default permissions (mode) of the sudoers file. In edit mode, the per‐\nmissions of the edited file will be set to the default. In check mode (-c), an error\nwill be reported if the file permissions are incorrect. This option is enabled by\ndefault if the sudoers file was not specified.\n", "flag": "-P", "long": "--perms" }, { "name": "-q --quiet", "content": "Enable quiet mode. In this mode details about syntax errors are not printed. This\noption is only useful when combined with the -c option.\n", "flag": "-q", "long": "--quiet" }, { "name": "-s --strict", "content": "Enable strict checking of the sudoers file. If an alias is referenced but not actu‐\nally defined or if there is a cycle in an alias, visudo will consider this a syntax\nerror. It is not possible to differentiate between an alias and a host name or user\nname that consists solely of uppercase letters, digits, and the underscore (‘’)\ncharacter.\n", "flag": "-s", "long": "--strict" }, { "name": "-V --version", "content": "Print the visudo and sudoers grammar versions and exit.\n\nA sudoers file may be specified instead of the default, /etc/sudoers. The temporary file\nused is the specified sudoers file with “.tmp” appended to it. In check-only mode only, ‘-’\nmay be used to indicate that sudoers will be read from the standard input. Because the pol‐\nicy is evaluated in its entirety, it is not sufficient to check an individual sudoers include\nfile for syntax errors.\n", "flag": "-V", "long": "--version" }, { "name": "Debugging and sudoers plugin arguments", "content": "visudo versions 1.8.4 and higher support a flexible debugging framework that is configured\nvia Debug lines in the sudo.conf(5) file.\n\nStarting with sudo 1.8.12, visudo will also parse the arguments to the sudoers plugin to\noverride the default sudoers path name, user-ID, group-ID, and file mode. These arguments,\nif present, should be listed after the path to the plugin (i.e., after sudoers.so). Multiple\narguments may be specified, separated by white space. For example:\n\nPlugin sudoerspolicy sudoers.so sudoersmode=0400\n\nThe following arguments are supported:\n\nsudoersfile=pathname\nThe sudoersfile argument can be used to override the default path to the sudoers file.\n\nsudoersuid=user-ID\nThe sudoersuid argument can be used to override the default owner of the sudoers file.\nIt should be specified as a numeric user-ID.\n\nsudoersgid=group-ID\nThe sudoersgid argument can be used to override the default group of the sudoers file.\nIt must be specified as a numeric group-ID (not a group name).\n\nsudoersmode=mode\nThe sudoersmode argument can be used to override the default file mode for the sudoers\nfile. It should be specified as an octal value.\n\nFor more information on configuring sudo.conf(5), refer to its manual.\n" } ] }, "ENVIRONMENT": { "content": "The following environment variables may be consulted depending on the value of the editor and\nenveditor sudoers settings:\n\nSUDOEDITOR Invoked by visudo as the editor to use\n\nVISUAL Used by visudo if SUDOEDITOR is not set\n\nEDITOR Used by visudo if neither SUDOEDITOR nor VISUAL is set\n", "subsections": [] }, "FILES": { "content": "/etc/sudo.conf Sudo front-end configuration\n\n/etc/sudoers List of who can run what\n\n/etc/sudoers.tmp Default temporary file used by visudo\n", "subsections": [] }, "DIAGNOSTICS": { "content": "In addition to reporting sudoers syntax errors, visudo may produce the following messages:\n", "subsections": [ { "name": "sudoers file busy, try again later.", "content": "Someone else is currently editing the sudoers file.\n" }, { "name": "/etc/sudoers: Permission denied", "content": "You didn't run visudo as root.\n" }, { "name": "you do not exist in the passwd database", "content": "Your user-ID does not appear in the system passwd database.\n" }, { "name": "Warning: {User,Runas,Host,Cmnd}_Alias referenced but not defined", "content": "Either you are trying to use an undeclared {User,Runas,Host,Cmnd}Alias or you have a\nuser or host name listed that consists solely of uppercase letters, digits, and the un‐\nderscore (‘’) character. In the latter case, you can ignore the warnings (sudo will\nnot complain). The message is prefixed with the path name of the sudoers file and the\nline number where the undefined alias was used. In -s (strict) mode these are errors,\nnot warnings.\n" }, { "name": "Warning: unused {User,Runas,Host,Cmnd}_Alias", "content": "The specified {User,Runas,Host,Cmnd}Alias was defined but never used. The message is\nprefixed with the path name of the sudoers file and the line number where the unused\nalias was defined. You may wish to comment out or remove the unused alias.\n" }, { "name": "Warning: cycle in {User,Runas,Host,Cmnd}_Alias", "content": "The specified {User,Runas,Host,Cmnd}Alias includes a reference to itself, either di‐\nrectly or through an alias it includes. The message is prefixed with the path name of\nthe sudoers file and the line number where the cycle was detected. This is only a\nwarning unless visudo is run in -s (strict) mode as sudo will ignore cycles when pars‐\ning the sudoers file.\n" }, { "name": "ignoring editor backup file", "content": "While processing a @includedir or #includedir, a file was found with a name that ends\nin ‘~’ or .bak. Such files are skipped by sudo and visudo.\n" }, { "name": "ignoring file name containing '.'", "content": "While processing a @includedir or #includedir, a file was found with a name that con‐\ntains a ‘.’ character. Such files are skipped by sudo and visudo.\n" }, { "name": "unknown defaults entry \"name\"", "content": "The sudoers file contains a Defaults setting not recognized by visudo.\n" } ] }, "SEE ALSO": { "content": "vi(1), sudo.conf(5), sudoers(5), sudo(8), vipw(8)\n", "subsections": [] }, "AUTHORS": { "content": "Many people have worked on sudo over the years; this version consists of code written primar‐\nily by:\n\nTodd C. Miller\n\nSee the CONTRIBUTORS.md file in the sudo distribution (https://www.sudo.ws/about/contribu‐\ntors/) for an exhaustive list of people who have contributed to sudo.\n", "subsections": [] }, "CAVEATS": { "content": "There is no easy way to prevent a user from gaining a root shell if the editor used by visudo\nallows shell escapes.\n", "subsections": [] }, "BUGS": { "content": "If you believe you have found a bug in visudo, you can submit a bug report at\nhttps://bugzilla.sudo.ws/\n", "subsections": [] }, "SUPPORT": { "content": "Limited free support is available via the sudo-users mailing list, see\nhttps://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search the archives.\n", "subsections": [] }, "DISCLAIMER": { "content": "visudo is provided “AS IS” and any express or implied warranties, including, but not limited\nto, the implied warranties of merchantability and fitness for a particular purpose are dis‐\nclaimed. See the LICENSE.md file distributed with sudo or https://www.sudo.ws/about/license/\nfor complete details.\n\nSudo 1.9.15p5 July 27, 2023 VISUDO(8)", "subsections": [] } }, "summary": "visudo — edit the sudoers file", "flags": [ { "flag": "-c", "long": "--check", "arg": null, "description": "Enable check-only mode. The existing sudoers file (and any other files it includes) will be checked for syntax errors. If the path to the sudoers file was not speci‐ fied, visudo will also check the file ownership and permissions (see the -O and -P options). A message will be printed to the standard output describing the status of sudoers unless the -q option was specified. If the check completes successfully, visudo will exit with a value of 0. If an error is encountered, visudo will exit with a value of 1." }, { "flag": "-f", "long": "--file", "arg": null, "description": "Specify an alternate sudoers file location, see below. As of version 1.8.27, the sudoers path can be specified without using the -f option." }, { "flag": "-h", "long": "--help", "arg": null, "description": "Display a short help message to the standard output and exit." }, { "flag": "-I", "long": "--no-includes", "arg": null, "description": "Disable the editing of include files unless there is a pre-existing syntax error. By default, visudo will edit the main sudoers file and any files included via @include or #include directives. Files included via @includedir or #includedir are never edited unless they contain a syntax error." }, { "flag": "-O", "long": "--owner", "arg": null, "description": "Enforce the default ownership (user and group) of the sudoers file. In edit mode, the owner of the edited file will be set to the default. In check mode (-c), an er‐ ror will be reported if the owner is incorrect. This option is enabled by default if the sudoers file was not specified." }, { "flag": "-P", "long": "--perms", "arg": null, "description": "Enforce the default permissions (mode) of the sudoers file. In edit mode, the per‐ missions of the edited file will be set to the default. In check mode (-c), an error will be reported if the file permissions are incorrect. This option is enabled by default if the sudoers file was not specified." }, { "flag": "-q", "long": "--quiet", "arg": null, "description": "Enable quiet mode. In this mode details about syntax errors are not printed. This option is only useful when combined with the -c option." }, { "flag": "-s", "long": "--strict", "arg": null, "description": "Enable strict checking of the sudoers file. If an alias is referenced but not actu‐ ally defined or if there is a cycle in an alias, visudo will consider this a syntax error. It is not possible to differentiate between an alias and a host name or user name that consists solely of uppercase letters, digits, and the underscore (‘’) character." }, { "flag": "-V", "long": "--version", "arg": null, "description": "Print the visudo and sudoers grammar versions and exit. A sudoers file may be specified instead of the default, /etc/sudoers. The temporary file used is the specified sudoers file with “.tmp” appended to it. In check-only mode only, ‘-’ may be used to indicate that sudoers will be read from the standard input. Because the pol‐ icy is evaluated in its entirety, it is not sufficient to check an individual sudoers include file for syntax errors." } ], "examples": [], "see_also": [ { "name": "vi", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/vi/1/json" }, { "name": "sudo.conf", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/sudo.conf/5/json" }, { "name": "sudoers", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/sudoers/5/json" }, { "name": "sudo", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/sudo/8/json" }, { "name": "vipw", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vipw/8/json" } ] }