Manual: pkill

PGREP(1)					User Commands					    PGREP(1)

NAME
       pgrep, pkill, pidwait - look up, signal, or wait for processes based on name and other attributes

SYNOPSIS
       pgrep [options] pattern
       pkill [options] pattern
       pidwait [options] pattern

DESCRIPTION
       pgrep  looks through the currently running processes and lists the process IDs which match the selec‐
       tion criteria to stdout.	 All the criteria have to match.  For example,

	      $ pgrep -u root sshd

       will only list the processes called sshd AND owned by root.  On the other hand,

	      $ pgrep -u root,daemon

       will list the processes owned by root OR daemon.

       pkill will send the specified signal (by default SIGTERM) to each process instead of listing them  on
       stdout.

       pidwait will wait for each process instead of listing them on stdout.

OPTIONS
       -signal
       --signal signal
	      Defines the signal to send to each matched process.  Either the numeric or the symbolic signal
	      name  can be used. In pgrep or pidwait mode only the long option can be used and has no effect
	      unless used in conjunction with --require-handler to filter to processes with a userspace sig‐
	      nal handler present for a particular signal.

       -c, --count
	      Suppress normal output; instead print a count of matching	 processes.   When  count  does	 not
	      match anything, e.g. returns zero, the command will return non-zero value. Note that for pkill
	      and  pidwait,  the count is the number of matching processes, not the processes that were suc‐
	      cessfully signaled or waited for.

       -d, --delimiter delimiter
	      Sets the string used to delimit each process ID in the output (by default a newline).   (pgrep
	      only.)

       -e, --echo
	      Display name and PID of the process being killed.	 (pkill only.)

       -f, --full
	      The  pattern is normally only matched against the process name.  When -f is set, the full com‐
	      mand line is used.

       -g, --pgroup pgrp,...
	      Only match processes in the process group IDs listed.  Process  group  0	is  translated	into
	      pgrep's, pkill's, or pidwait's own process group.

       -G, --group gid,...
	      Only  match processes whose real group ID is listed.  Either the numerical or symbolical value
	      may be used.

       -i, --ignore-case
	      Match processes case-insensitively.

       -l, --list-name
	      List the process name as well as the process ID.	(pgrep only.)

       -a, --list-full
	      List the full command line as well as the process ID.  (pgrep only.)

       -n, --newest
	      Select only the newest (most recently started) of the matching processes.

       -o, --oldest
	      Select only the oldest (least recently started) of the matching processes.

       -O, --older secs
	      Select processes older than secs.

       -P, --parent ppid,...
	      Only match processes whose parent process ID is listed.

       -s, --session sid,...
	      Only match processes whose process session ID is listed.	Session	 ID  0	is  translated	into
	      pgrep's, pkill's, or pidwait's own session ID.

       -t, --terminal term,...
	      Only match processes whose controlling terminal is listed.  The terminal name should be speci‐
	      fied without the "/dev/" prefix.

       -u, --euid euid,...
	      Only  match  processes  whose effective user ID is listed.  Either the numerical or symbolical
	      value may be used.

       -U, --uid uid,...
	      Only match processes whose real user ID is listed.  Either the numerical or  symbolical  value
	      may be used.

       -v, --inverse
	      Negates  the  matching.	This  option  is  usually  used in pgrep's or pidwait's context.  In
	      pkill's context the short option is disabled to avoid accidental usage of the option.

       -w, --lightweight
	      Shows all thread ids instead of pids in pgrep's or pidwait's context.  In pkill's context this
	      option is disabled.

       -x, --exact
	      Only match processes whose names (or command lines if -f is specified) exactly match the	pat‐
	      tern.

       -F, --pidfile file
	      Read PIDs from file.  This option is more useful for pkill or pidwait than pgrep.

       -L, --logpidfile
	      Fail if pidfile (see -F) not locked.

       -r, --runstates D,R,S,Z,...
	      Match only processes which match the process state.

       -A, --ignore-ancestors
	      Ignore  all  ancestors of pgrep, pkill, or pidwait.  For example, this can be useful when ele‐
	      vating with sudo or similar tools.

       -H, --require-handler
	      Only match processes with a userspace signal handler present for the signal to be sent.

       --cgroup name,...
	      Match on provided control group (cgroup) v2 name. See cgroups(8)

       --ns pid
	      Match processes that belong to the same namespaces. Required to run as root to match processes
	      from other users. See --nslist for how to limit which namespaces to match.

       --nslist name,...
	      Match only the provided namespaces. Available namespaces: ipc, mnt, net, pid, user, uts.

       -q, --queue value
	      Use sigqueue(3) rather than kill(2) and the value argument is used to specify an integer to be
	      sent with the signal. If the receiving process has installed a handler for this  signal  using
	      the  SA_SIGINFO  flag  to sigaction(2), then it can obtain this data via the si_value field of
	      the siginfo_t structure.

       -V, --version
	      Display version information and exit.

       -h, --help
	      Display help and exit.

OPERANDS
       pattern
	      Specifies an Extended Regular Expression for matching against the	 process  names	 or  command
	      lines.

EXAMPLES
       Example 1: Find the process ID of the named daemon:

	      $ pgrep -u root named

       Example 2: Make syslog reread its configuration file:

	      $ pkill -HUP syslogd

       Example 3: Give detailed information on all xterm processes:

	      $ ps -fp $(pgrep -d, -x xterm)

       Example 4: Make all chrome processes run nicer:

	      $ renice +4 $(pgrep chrome)

EXIT STATUS
       0      One  or more processes matched the criteria. For pkill and pidwait, one or more processes must
	      also have been successfully signalled or waited for.
       1      No processes matched or none of them could be signalled.
       2      Syntax error in the command line.
       3      Fatal error: out of memory etc.

NOTES
       The process name used for matching is  limited  to  the	15  characters	present	 in  the  output  of
       /proc/pid/stat.	 Use  the  -f  option to match against the complete command line, /proc/pid/cmdline.
       Threads may not have the same process name as the parent process but will have the same command line.

       The running pgrep, pkill, or pidwait process will never report itself as a match.

       The -O --older option will silently fail if /proc is mounted with the subset=pid option.

BUGS
       The options -n and -o and -v can not be combined.  Let me know if you need to do this.

       Defunct processes are reported.

       pidwait requires the pidfd_open(2) system call which first appeared in Linux 5.3.

SEE ALSO
       ps(1), regex(7), signal(7), sigqueue(3), killall(1), skill(1), kill(1), kill(2), cgroups(8).

AUTHOR
       Kjetil Torgrim Homme

REPORTING BUGS
       Please send bug reports to procps@freelists.org

procps-ng					 2023-01-16					    PGREP(1)