Running in the background is quite different from "daemonizing" as stated by the other posters. You can use a simple daemonize function call in your code, though:

sub daemonize {
    # usage: daemonize( [errorlog path, activitylog path] )
    
    my $errlog=shift;
    my $actlog=shift;

    $errlog ||="/dev/null";
    $actlog ||="/dev/null";

    chdir '/'
      or die "can't chdir to root : $!";

    open( STDIN, '</dev/null' )
      or die "can't redirect STDIN : $!";
    open( STDERR, ">>$errlog" )
      or die "can't redirect STDERR : $!";
    open( STDOUT, ">>$actlog" )
      or die "can't redirect STDOUT : $!");

    fork and exit;

    return 1;
}
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