man > chpst(8)

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📝 NAME

chpst - runs a program with a changed process state

🚀 Quick Reference

Use Case	Command	Description
Run as different user	chpst -u user:group prog	Set uid/gid and supplementary groups before running prog
Set environment from directory	chpst -e dir prog	Load environment variables from files in dir
Chroot and run	chpst -/ root prog	Change root directory to root before starting prog
Set resource limits	chpst -m 100M -d 50M -o 100 -p 50 prog	Limit memory, data segment, open files, processes per uid
Lock file exclusive (wait)	chpst -l /tmp/lock prog	Obtain an exclusive lock; wait if locked
Lock file fail if busy	chpst -L /tmp/lock prog	Obtain an exclusive lock; fail immediately if locked
Verbose mode	chpst -v prog	Print verbose messages to stderr
Close standard streams	chpst -0 -1 -2 prog	Close stdin, stdout, stderr before starting prog

📋 SYNOPSIS

chpst  [-vVP012]  [-u user] [-U user] [-b argv0] [-e dir] [-/ root] [-n inc] [-l|-L lock] [-m
       bytes] [-d bytes] [-o n] [-p n] [-f bytes] [-c bytes] [-t seconds] prog

🧠 DESCRIPTION

prog consists of one or more arguments.

chpst changes the process state according to the given options, and runs prog.

⚙️ OPTIONS

• 👤 -u [:]user[:group]
  setuidgid. Set uid and gid to the user's uid and gid, as found in /etc/passwd. If user is followed by a colon and a group, set the gid to group's gid, as found in /etc/group, instead of user's gid. If group consists of a colon-separated list of group names, chpst sets the group ids of all listed groups. If user is prefixed with a colon, the user and all group arguments are interpreted as uid and gids respectively, and not looked up in the password or group file. All initial supplementary groups are removed.
• 🌐 -U [:]user[:group]
  envuidgid. Set the environment variables $UID and $GID to the user's uid and gid, as found in /etc/passwd. If user is followed by a colon and a group, set $GID to the group's gid, as found in /etc/group, instead of user's gid. If user is prefixed with a colon, the user and group arguments are interpreted as uid and gid respectively, and not looked up in the password or group file.
• 🏷️ -b argv0
  argv0. Run prog with argv0 as the 0th argument.
• 📁 -e dir
  envdir. Set various environment variables as specified by files in the directory dir: If dir contains a file named k whose first line is v, chpst removes the environment variable k if it exists, and then adds the environment variable k with the value v. The name k must not contain =. Spaces and tabs at the end of v are removed, and nulls in v are changed to newlines. If the file k is empty (0 bytes long), chpst removes the environment variable k if it exists, without adding a new variable.
• 🏠 -/ root
  chroot. Change the root directory to root before starting prog.
• 🌟 -n inc
  nice. Add inc to the nice(2) value before starting prog. inc must be an integer, and may start with a minus or plus.
• 🔒 -l lock
  lock. Open the file lock for writing, and obtain an exclusive lock on it. lock will be created if it does not exist. If lock is locked by another process, wait until a new lock can be obtained.
• 🔐 -L lock
  The same as -l, but fail immediately if lock is locked by another process.
• 🧠 -m bytes
  limit memory. Limit the data segment, stack segment, locked physical pages, and total of all segment per process to bytes bytes each.
• 📊 -d bytes
  limit data segment. Limit the data segment per process to bytes bytes.
• 🔢 -o n
  limit open files. Limit the number of open file descriptors per process to n.
• 👥 -p n
  limit processes. Limit the number of processes per uid to n.
• 📦 -f bytes
  limit output size. Limit the output file size to bytes bytes.
• 💾 -c bytes
  limit core size. Limit the core file size to bytes bytes.
• ⏱️ -t seconds
  limit CPU time. Limit CPU time to seconds seconds, delivering a SIGXCPU thereafter.
• 📢 -v
  verbose. Print verbose messages to standard error. This includes warnings about limits unsupported by the system.
• ℹ️ -V
  version string. Print a version string to standard error.
• 👥 -P
  pgrphack. Run prog in a new process group.
• 🔴 -0
  Close standard input before starting prog.
• 🟢 -1
  Close standard output before starting prog.
• 🟡 -2
  Close standard error before starting prog.

🚪 EXIT CODES

chpst exits 100 when called with wrong options. It prints an error message and exits 111 if it has trouble changing the process state. Otherwise its exit code is the same as that of prog.

🔄 EMULATION

If chpst is called as envdir, envuidgid, pgrphack, setlock, setuidgid, or softlimit, it emulates the functionality of these programs from the daemontools package respectively.

📚 SEE ALSO

sv(8), runsv(8), setsid(2), runit(8), runit-init(8), runsvdir(8), runsvchdir(8)

http://smarden.org/runit/
http://cr.yp.to/daemontools.html

👤 AUTHOR

Gerrit Pape <pape AT smarden.org>

📝 NAME 🚀 Quick Reference 📋 SYNOPSIS 🧠 DESCRIPTION ⚙️ OPTIONS 🚪 EXIT CODES 🔄 EMULATION 📚 SEE ALSO 👤 AUTHOR