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Full Discussion: [KSH/Bash] Starting a parent process from a child process?
Top Forums Shell Programming and Scripting [KSH/Bash] Starting a parent process from a child process? Post 302408483 by alister on Monday 29th of March 2010 03:46:53 PM
Old 03-29-2010
Quote:
Originally Posted by bakunin
Start the scripts in background and with "nohup". see the man page of "nohup" for details.

If you start them this they will no longer stop when the parent process is killed.
That probably won't help, unless the controlling terminal is lost or a SIGHUP is being sent with kill. I assume that he's using either ^C (SIGINT) at the keyboard or a typical kill command (SIGTERM); nohup will not prevent a process from receiving either of these.

Your pid file suggestion is a good one though. Something along the lines of:
Code:
$ cat a.sh
#!/bin/sh

echo $$ > a.pid
./b.sh &
#Do whatever script a is supposed to do


$ cat b.sh
#!/bin/sh

echo $$ > b.pid
./c.sh &
# Do whatever script b is supposed to do


$ cat c.sh
#!/bin/sh

# Do whatever script c is suposed to do
kill $(cat a.pid b.pid)
# Make needed changes
./a.sh &

Although any external executables running asynchronously at the time that the parent shell receives SIGTERM from kill will linger until they're done. If that's an issue, then a.sh would need to be started asynchronously and any signals sent to its process group (which b, c, a, b ... and further iterations in the cycle would inherit).

Regards,
Alister
Last edited by alister; 03-29-2010 at 05:32 PM..
 

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LEARN ABOUT XFREE86

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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