Stop processes

Process communicate with each other using signals. A process signal is a predefined message that process recognize and may choose to ignore or act on.

Linux Process Signal

• 1 HUG Hangs up
• 2 INT Interrupts
• 3 QUIT Stop running
• 9 KILL Unconditionally terminates
• 11 SEGV Produces segment violation
• 15 TERM Terminate if possible
• 17 STOP Stops unconditionally, but doesn't terminate
• 18 TSTP Stops or pause, but continues to run in background
• 19 CONT Resume execution after STOP or TSTP

The kill command

The kill command allows you to send signals to processes based on their process ID.(Default TERM)

$ sudo kill 3940
$ sudo kill -9 3940
$ sudo kill -s HUP 3940

The killall command

The killall command is a powerful way to stop processes by using their names rather than the PID numbers.(wildcard characters)

# killall nginx*