in reply to Checking for multiple instances

My favorite trick is ensuring that the file contains __END__, and then flocking DATA, which is open on the program file itself. No need to create a sentinel file that way.

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

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Re^2: Checking for multiple instances
by Your Mother (Archbishop) on Sep 24, 2004 at 22:06 UTC

    That is very cool. Not to pester but would you give a snippet (or point to one) showing it in action?

[reply]
      I can't find my working example right now, but from memory, something like this: 
      #!/usr/bin/perl
use Fcntl qw(LOCK_EX LOCK_NB);
flock DATA, LOCK_EX | LOCK_NB or die "Already executing!";
... rest of code ...
# do not remove this __END__!
__END__

      [download]

      -- Randal L. Schwartz, Perl hacker
      Be sure to read my standard disclaimer if this is a reply.

[reply]
[d/l]

        Thanks, that's plenty, I'm sure. I was just a'scared there might be a trick to it that was different from vanilla flock'ing.

[reply]

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