kill - send a signal to a process


kill [ -signal | -s signal ] pid ... kill [ -L | -V, --version ] kill -l [ signal ]


The default signal for kill is TERM. Use -l or -L to list available signals. Particularly useful signals include HUP, INT, KILL, STOP, CONT, and 0. Alternate signals may be specified in three ways: -9 -SIGKILL -KILL. Negative PID values may be used to choose whole process groups; see the PGID column in ps command output. A PID of -1 is special; it indicates all processes except the kill process itself and init.


The signals listed below may be available for use with kill. When known constant, numbers and default behavior are shown.

Name Num Action Description
0 0 n/a exit code indicates if a signal may be sent ALRM 14 exit HUP 1 exit INT 2 exit KILL 9 exit cannot be blocked PIPE 13 exit POLL exit PROF exit TERM 15 exit USR1 exit USR2 exit VTALRM exit STKFLT exit might not be implemented PWR ignore might exit on some systems WINCH ignore CHLD ignore URG ignore TSTP stop might interact with the shell TTIN stop might interact with the shell TTOU stop might interact with the shell STOP stop cannot be blocked CONT restart continue if stopped, otherwise ignore ABRT 6 core FPE 8 core ILL 4 core QUIT 3 core SEGV 11 core TRAP 5 core SYS core might not be implemented EMT core might not be implemented BUS core core dump might fail XCPU core core dump might fail XFSZ core core dump might fail


Your shell (command line interpreter) may have a built-in kill command. You may need to run the command described here as /bin/kill to solve the conflict.


kill -9 -1
Kill all processes you can kill.

kill -l 11
Translate number 11 into a signal name.

kill -L
List the available signal choices in a nice table.

kill 123 543 2341 3453
Send the default signal, SIGTERM, to all those processes.


pkill(1), skill(1), kill(2), renice(1), nice(1), signal(7), killall(1).


This command meets appropriate standards. The -L flag is Linux- specific.


Albert Cahalan <> wrote kill in 1999 to replace a bsdutils one that was not standards compliant. The util-linux one might also work correctly.

Please send bug reports to <>