Re: backgrounding a script

[Bob McGowan <rmcgowan@veritas.com>]

MiKe McClain wrote:
> Is there a way for a script to background itself?
> Thanks,
> Mike
> 
> 

Yes.  But you gotta be careful, it's very easy to get a run away process
series.  The basic idea is that the script has to rerun itself in the
background and exit.  The way I do this is to set a flag in the first pass
and *export* it, so the second pass can skip the first pass code.  Like
this:

#!/bin/bash

# Got to be careful, we don't want to go into an infinite loop of scripts.

if [ ! "$DoNotBGMe" ]
then
  # Set this so we don't try to rerun this script more than one time.
  export DoNotBGMe=yes
  # Background self.  First, get full path to self.  This usage of 'type'
  # may be specific to the bash shell.
  me=$(type -p bgself)
  echo Before backgrounding:  $$
  $me &
  exit
fi

echo After backgrounding:  $$
echo "I'm running!"
# End of script

You can remove the 3 echo commands, they're there for illustration only.
The code you want to have actually run goes after the 'if' statement.

Bob McGowan

PS:  Forgot to mention, you may also not need to do the 'me=$(type...)'
part, I do it so I can verify I'm actually running the script I think I'm
running.  Problems of this type can happen if you explicitly set the PATH
being used by script (something you should do if the script is to become a
production level tool, used by many users).

bob