Fast process lookup and signaling

pgrep and pkill commands used for to lookup a process by attribute.

To quick find all instances of ssh running, for user root, execute the following command:

$ pgrep -u root -l ssh

To kill a process, or send a signal use the pkill.

For example, to make syslog reread its configuration file:

$ pkill -HUP syslogd

Another command command is pidof that can tell you how many processes are running. This can be useful for detecting DOS attacks.

$ pidof sshd 
4783 4781 30008 30006 29888 29886 2246

Above there are 7 sshd’s running.

Reference: “Tcpdump, Raw Socket and Libpap Tutorial” at