Kill Process In Ubuntu Linux

How can I kill a process using the bash command prompt? Do I always need to kill the process using PID?

To kill processes by name use the killall command. The syntax is as follows:

killall -SIGNAME process-name
 

The default signal for kill is TERM (terminate process). To list available signals, enter:
$ kill -l
The following are useful signals and used frequently by sys admins and Ubuntu users:

1. SIGHUP (1) - Hangup detected on controlling terminal or death of controlling process.
2. SIGINT (2) - Interrupt from keyboard.
3. SIGKILL (9) - Kill signal i.e. kill running process.
4. SIGSTOP (19) - Stop process.
5. SIGCONT (18) - Continue process if stopped.

Examples - Ubuntu Linux: Killing Process

To kill all apache2 process, enter:
$ sudo killall -9 apache2
To kill all firefox process, enter:
$ sudo killall -9 firefox-bin
You can also use the pkill command as follows to kill all php-cgi process, enter:
$ pkill -KILL php-cgi
The -u option will kill only processes whose effective user ID is set to vivek:
$ sudo pkill -KILL -u vivek php-cgi

See also:

• Sending signal to Processes (http://bash.cyberciti.biz/guide/Sending_signal_to_Processes)