Guide to Unix/Commands/Process Management

nohup
nohup lets you run a program in a way which makes it ignore hangup signals. This can be used to make a program continue running after a user has logged out. The output of the program is redirected from the standard output to the file nohup.out.

Examples:

$ nohup wget http://foo.org/foo_list.gz nohup: appending output to `nohup.out' $

Links:
 * nohup, opengroup.org
 * nohup, freebsd.org
 * 23.4 nohup in GNU Coreutils manual, gnu.org

ps
ps displays a list of current processes and their properties.

Examples:

Processes owned by the current user:

$ ps PID TTY         TIME CMD 17525 pts/0   00:00:00 su 17528 pts/0    00:00:00 bash 17590 pts/0   00:00:00 ps where pid is process id.

All processes:

$ ps -A

Links:
 * ps, opengroup.org
 * ps man page, man.cat-v.org

kill
kill is used to send termination signals to processes.

Examples

To send the kill signal to the processes with process id 17525,

$ kill -9 17525

To send the kill signal to all processes,

$ kill -9 -1

see Guide to Unix/Commands/Process Management/Kill

Links:
 * kill, opengroup.org
 * kill man page, man.cat-v.org
 * 24.1 kill in GNU Coreutils manual, gnu.org

pgrep
pgrep search and kill system processes

Example: Check if apache webserver is running. $ pgrep -f apache 5580 5581  5582  5583  5584  5585 or $ svcs -a | grep -i apache.

Links:
 * pgrep, freebsd.org
 * pgrep, manpages.ubuntu.com

pkill
Stop xterm program with 'pkill' program:

$ pkill -9 xterm

Tips: Display all the process of a user $ pgrep -l -u arky 894 bash 895 bash 897 bash 898 bash 899 bash 1045 links 1396 startx 1407 xinit 1411 openbox 1412 xterm 1413 xfaces 1414 xsetroot 1415 emacs

Links:
 * pkill, freebsd.org
 * pkill, manpages.ubuntu.com

pidof
pidof display Process ID (PID) of a task

Example: Display the PID of emacs process: $ pidof emacs 1415

Links:
 * pidof, manpages.ubuntu.com

killall
killall kill a process by name

Example:

Kill the 'xfaces' program: $ killall xfaces

Links:
 * killall, freebsd.org
 * killall, manpages.ubuntu.com