pgrep / pkill

Kill processes by a full or partial name.

Syntax
      pgrep [-flvx] [-d delimiter] [-n|-o] [-P ppid,...] [-g pgrp,...]
         [-s sid,...] [-u euid,...] [-U uid,...] [-G gid,...]
            [-t term,...] [pattern]

      pkill [-signal] [-fvx] [-n|-o] [-P ppid,...] [-g pgrp,...]
         [-s sid,...] [-u euid,...] [-U uid,...] [-G gid,...]
            [-t term,...] [pattern]

Key
   pattern
       An Extended Regular Expression to match process names or command lines.

   -d delimiter
       Set the string used to delimit each process ID in the output
       (by default a newline). (pgrep only.) 
   -f
       The pattern is normally only matched against the process name.
       When -f is set, the full command line is used. 
   -g pgrp,...
       Only match processes in the process group IDs listed.
       Process group 0 is translated into pgrep’s or pkill’s own process group. 
   -G gid,...
       Only match processes whose real group ID is listed.
       Either the numerical or symbolical value can be used. 
   -l
       List the process name as well as the process ID. (pgrep only.) 
   -n
       Select only the newest (most recently started) of the matching processes. 
   -o
       Select only the oldest (least recently started) of the matching processes. 
   -P ppid,...
       Only match processes whose parent process ID is listed. 
   -s sid,...
       Only match processes whose process session ID is listed.
       Session ID 0 is translated into pgrep’s or pkill’s own session ID. 
   -t term,...
       Only match processes whose controlling terminal is listed.
       The terminal name should be specified without the "/dev/" prefix. 
   -u euid,...
       Only match processes whose effective user ID is listed.
       Either the numerical or symbolical value can be used. 
   -U uid,...
       Only match processes whose real user ID is listed.
       Either the numerical or symbolical value can be used. 
   -v
       Negates the matching. 
   -x
       Only match processes whose name (or command line if -f is specified)
       exactly match the pattern. 
   -signal
       Defines the signal to send to each matched process.
       Either the numeric or the symbolic signal name can be used. (pkill only.)

pgrep searches the process table on the running system and prints the process IDs of all processes that match the criteria given on the command line.

pkill searches the process table on the running system and signals all processes that match the criteria given on the command line.

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.

Common Kill Signals
Signal name Signal value Effect
SIGHUP 1 Hangup
SIGINT 2 Interrupt from keyboard
SIGQUIT 3 Quit
SIGABRT 6 Cancel
SIGKILL 9 Kill signal
SIGTERM 15 Termination signal - allow an orderly shutdown
SIGSTOP 17,19,23 Stop the process

Exit Status

1. One or more processes matched the criteria.
2. No processes matched.
3. Syntax error in the command line.
4. Fatal error: out of memory etc.

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 netscape processes run nicer:

$ renice +4 'pgrep netscape'

“Somebody should tell us, right at the start of our lives, that we are dying. Then we might live life to the limit, every minute of every day. Do it! I say. Whatever you want to do, do it now! There are only so many tomorrows” ~ Pope Paul VI

Related Linux commands

ps - List running processes (returns PID).
kill - Kill a process by specifying its PID.
killall - Kill processes by name.
bg - Put a process in the background.
fg - Put a process in the foreground.
w - Show who is logged on and what they are doing.
Equivalent Windows command: TSKILL - End a running process.


 
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