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Ch4 Signals - pkill option -H

I have a question about signals I can't find the answer myself.
In the documentation and also in the man pages on this https://linux.die.net/man/1/pkill the example to Make syslog reread its configuration file: pkill -HUP syslogd
I can't find where the option -H comes from.
What is the meaning of the -H option in this?

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  • Posts: 16

    OK, to answer myself, it looks like -H is not one of the options. -HUP stands for H(ang)UP. see https://www.pair.com/support/kb/paircloud-using-kill-killall-and-pkill/#sighup
    quote from the description:

    The SIGHUP (1) signal is now used to tell a process to reload the configuration file and re-initialize.

  • Posts: 16

    edit: typo H(ang) UP should be H(ung) UP.

  • Posts: 16

    Now I am thinking of it, I wrongly assumed -HUP being options. I understand it is a signal, not options for a signal. Am I correct?

  • Posts: 916
    1. c8:/tmp>kill -l
    2. 1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP
    3. 6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1
    4. 11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM
    5. 16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP
    6. 21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ
    7. 26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO 30) SIGPWR
    8. 31) SIGSYS 34) SIGRTMIN 35) SIGRTMIN+1 36) SIGRTMIN+2 37) SIGRTMIN+3
    9. .....

    kill - SIGHUP pid is the same askill -1 pid

  • Hi @robbnl ,

    To complement what Coop said, you can find a brief description about each signal in the man page for signal(7).

    Regards,
    Luis.

  • Posts: 22
    edited October 2020

    Also, I think that -HUP as a method for reloading process after config changes doesn't work for all "programs", of course, because each program process is free to handle/ignore specific SIGNALS, just the SIGKILL (9) cant be ignored

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