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 this 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⟩