Just make sure you do your locking properly, you can have a look at flock - lordy me.... for a lengthy discussion of the various traps that come with using flock.

Usually I use a dedicated (empty) lock file and then I go about playing with the various data files I use:

sub db_lock()
  { open LOCK, ">$LOCK_FILE" || die "$0: [error] Can't open lock file:
+ $!\n";
    flock( LOCK, LOCK_EX) || die "$0: [error] during lock: $!\n";
  }
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