Linux / Unix: killall Command Examples

I am a new Linux and Unix user and sysadmin. How do I kill processes by name instead by PID on Linux or Unix-like systems?

The kill command kills process by PID (process ID). To kill process by name, use killall command.[donotprint]

1. Linux
2. Apple OS X Unix
3. FreeBSD

Purpose

Kill process or commands by name on Linux/FreeBSD/Apple OS X Unix.

Syntax

The basic syntax is as follows:

killall process
OR
killall -SIGNAL process
OR
killall command
OR
killall -15 command
OR
killall -u {userName} processName
OR
killall -t {ttyName} processName
OR
killall [options] processName

Understanding Linux and Unix signals

To display list of all known signal names, enter:

$ killall -l

Sample outputs:

HUP INT QUIT ILL TRAP ABRT IOT BUS FPE KILL USR1 SEGV USR2 PIPE ALRM TERM
STKFLT CHLD CONT STOP TSTP TTIN TTOU URG XCPU XFSZ VTALRM PROF WINCH IO PWR SYS
UNUSED

By default SIGTERM/TERM (15) is sent to process, if not signal is given to the killall command. The following signals are usefully used by both users and sysadmins:

You can kill your own process. To kill all other users process you need to the privileged root user.

killall command examples

In this example, start a process called xeyes as follows:
$ xeyes &
Sample outputs:

[1] 3514

To kill xeyes process, type:
$ killall xeyes
OR Send a signal as a name:
$ killall -TERM xeyes
OR send a signal numerically:
$ killall -15 xeyes
Sample outputs:

[1]+  Terminated              xeyes

To get more verbose output on screen pass the -v option:
$ killall -v -TERM xeyes
Sample outputs:

Killed xeyes(4279) with signal 15
[1]+  Terminated              xeyes

How do I kill process owned by the specific user?

The syntax is as follows:
killall -u {user} process
To kill php-cgi process owned by nixcraft, user:
# killall -u nixcraft php-cgi
OR
# killall -TERM -u nixcraft php-cgi
OR
# killall -KILL -u nixcraft php-cgi

How do I kill process running on specific tty?

To show the name the terminal use tty command:
$ tty
Sample outputs:

/dev/pts/0

You can also use ps command or w command to display tty:
$ ps
$ w
The syntax is as follows to kill firefox process running pts/0:
killall -t pts/0 firefox
OR
killall -t pts/0 firefox
OR
killall -t pts/0 firefox
OR combine both username and tty as follows:
# killall -u nixcraft -t pts/0 firefox

Kill process group

In this example, kill process group called php-cgi instead of process name:
$ sudo killall -KILL -v -g php-cgi
Sample outputs:

Fig. 01: killall command in action

Confirm process killing

The killall command can ask for interactive confirmation before killing process by passing the -i option as follows:
$ killall -i gedit
Sample outputs:

Animated gif 01: killall command demo

Kill process by given time

Pass the -y TIME option to kill processes younger than given TIME. Pass the -o TIME option to kill processes older than given TIME. TIME can be expressed in the following float format then the unit:

1. s for seconds
2. m for minutes
3. h for hours
4. d for days
5. w for weeks
6. M for Months
7. y for years

Here are some examples for timely process killing:

# Kill firefox command younger than 3 days
killall -y 3d  firefox
 
# Kill top command  younger than 2 minutes
killall -y 2m  firefox
 
# Kill perl-cgi command older than 1 months
killall -o 1M  perl
 
# Kill nginx server older than 2 years
killall -o 2y  nginx
 
# Kill ping command  older than 2 weeks with confirmation and owned by vivek user
killall -u vivek -i -o 2w  ping

killall command options

From the killall(1) command man page:

Related media

This tutorial is also available in a quick video format:

See also

• killall(1) Linux/Unix command man page