The kill command is used to send a specific signal to a process. The default signal sent is 'SIGTERM' (15), which terminates the process. By using kill -l' (lowercase 'L'), you can list all available signal names and numbers. If the default 'SIGTERM' signal doesn't terminate a process, you can escalate the intensity by using the 'SIGKILL' (9) signal.
The basic usage of kill -l is either kill -s signal name or kill -#, where '#' is the signal number. For instance, kill -s SIGKILL is equivalent to kill -9.
Example:| $ kill -l ←List all signal numbers 1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM 16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP . . . |
| $ seq 1000000000 > /dev/null & ←Run 'seq' in the background [1] 20468 $ kill %+1 ←Terminate the background process [1]+ Terminated seq 1000000000 > /dev/null |