Kill signals

SIGNALS The signals  listed  below  may  be available for use with kill. When known constant, numbers and default behavior are shown.

Name    Num   Action    Description 

0         0   n/a       exit code indicates if a signal may be sent ALRM     14   exit HUP       1   exit INT       2   exit KILL      9   exit      this signal may not be blocked PIPE     13   exit POLL          exit PROF          exit TERM     15   exit USR1          exit USR2          exit VTALRM        exit STKFLT        exit      may not be implemented PWR           ignore    may exit on some systems WINCH         ignore CHLD          ignore URG           ignore TSTP          stop      may interact with the shell TTIN          stop      may interact with the shell TTOU          stop      may interact with the shell STOP          stop      this signal may not be blocked CONT          restart   continue if stopped, otherwise ignore ABRT      6   core FPE       8   core ILL       4   core QUIT      3   core SEGV     11   core TRAP      5   core SYS           core      may not be implemented EMT           core      may not be implemented BUS           core      core dump may fail

XCPU          core      core dump may fail XFSZ          core      core dump may fail

Mostly used in real life are 15 (default), 1 (allowing cleanup) and 9 (as last resort). But read here why you should avoid 9 if possible: Useless use of kill -9. Its better to try in this order: 15 (default), 2 (INT), 1 (HUP), 9 (KILL).