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Full Discussion: help with understanding script
Top Forums UNIX for Dummies Questions & Answers help with understanding script Post 302474219 by iluvsushi on Tuesday 23rd of November 2010 03:48:51 PM
Old 11-23-2010
help with understanding script
i am trying to understand this script example. the text does not explain it. can someone tell me briefly what each of the functions do. any help will be appreciated.
Code:
#!/bin/bash

killtree() {
    local _pid=$1
    local _sig=${2-TERM}
    for _child in $(ps -o pid --no-headers --ppid ${_pid}); do
        killtree ${_child} ${_sig}
    done
    kill -${_sig} ${_pid}
}

if [ $# -eq 0 -o $# -gt 2 ]; then
    echo "Usage: $(basename $0) <pid> [signal]"
    exit 1
fi

killtree $@
#
#       ......
#
while [ $(ps -p $! -o etime= | tr -d ": ") -lt 10000 ]
do
  sleep 60
done 2> /dev/null

kill -s SIGHUP $!

function my_ps()
function killps()   # kill by process name
{
   local pid pname sig="-TERM"   # default signal
   if [ "$#" -lt 1 ] || [ "$#" -gt 2 ]; then
       echo "Usage: killps [-SIGNAL] pattern"
       return;
   fi
   if [ $# = 2 ]; then sig=$1 ; fi
   for pid in $(.............) ; do
       pname=$(................... )
       if ask "Kill process $pid <$pname> with signal $sig?"
           then kill $sig $pid
       fi
   done
}
_killall ()
{
    COMPREPLY=( $( /bin/ps -u $USER -o comm  | \
        sed -e '1,1d' -e 's#[]\[]##g' -e 's#^.*/##'| \
        awk '{if ($0 ~ /^$USER/) print $0}' ))

    return 0
}
complete -F _killall killall killps

Last edited by Scott; 11-23-2010 at 04:54 PM.. Reason: Code tags, please...
 

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LEARN ABOUT X11R4

kill

KILL(1)                                                            User Commands                                                           KILL(1)

NAME

       kill - send a signal to a process

SYNOPSIS

       kill [options] <pid> [...]

DESCRIPTION

       The  default  signal  for kill is TERM.  Use -l or -L to list available signals.  Particularly useful signals include HUP, INT, KILL, STOP,
       CONT, and 0.  Alternate signals may be specified in three ways: -9, -SIGKILL or -KILL.  Negative PID values may be  used  to  choose  whole
       process  groups;  see  the  PGID  column  in ps command output.  A PID of -1 is special; it indicates all processes except the kill process
       itself and init.

OPTIONS

       <pid> [...]
              Send signal to every <pid> listed.

       -<signal>
       -s <signal>
       --signal <signal>
              Specify the signal to be sent.  The signal can be specified by using name or number.  The behavior of signals is explained  in  sig-
              nal(7) manual page.

       -l, --list [signal]
              List signal names.  This option has optional argument, which will convert signal number to signal name, or other way round.

       -L, --table
              List signal names in a nice table.

       NOTES  Your shell (command line interpreter) may have a built-in kill command.  You may need to run the command described here as /bin/kill
              to solve the conflict.

EXAMPLES

       kill -9 -1
              Kill all processes you can kill.

       kill -l 11
              Translate number 11 into a signal name.

       kill -L
              List the available signal choices in a nice table.

       kill 123 543 2341 3453
              Send the default signal, SIGTERM, to all those processes.

SEE ALSO

       kill(2), killall(1), nice(1), pkill(1), renice(1), signal(7), skill(1)

STANDARDS

       This command meets appropriate standards. The -L flag is Linux-specific.

AUTHOR

       Albert Cahalan <albert@users.sf.net> wrote kill in 1999 to replace a bsdutils one that was not standards  compliant.   The  util-linux  one
       might also work correctly.

REPORTING BUGS

       Please send bug reports to <procps@freelists.org>

procps-ng                                                          October 2011                                                            KILL(1)
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