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 selection 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  signal  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 successfully 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 command 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 specified 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 pattern.

       -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 elevating 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 ⟨kjetilho@ifi.uio.no⟩

REPORTING BUGS

       Please send bug reports to ⟨procps@freelists.org⟩