PGREP
Section: User Commands (1)
Updated: 2020-06-04
Page Index
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.
(pkill
only.)
- -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
pkillorpidwait
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.
- --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.
The running
pgrep,
pkill,
or
pidwait
process will never report itself as a
match.
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.
SEE ALSO
ps(1),
regex(7),
signal(7),
sigqueue(3),
killall(1),
skill(1),
kill(1),
kill(2)
AUTHOR
Kjetil Torgrim Homme
REPORTING BUGS
Please send bug reports to