Perl version: 5.8.0
Redhat version: Red Hat 5.3

##</code><code>##

#!/usr/bin/perl

use warnings;
use strict;
use Switch;

file_version_1();
file_version_2();

sub file_version_1 {
    open( my $fh, '<', '/tmp/test_file.txt' ) or die( "Error: $!" );
    while( my $line = <$fh> ) {
        print "$line\n";
    }
    close( $fh );
}

sub file_version_2 {
    open ( FH, '/tmp/test_file.txt' ) or die ("Error: $!" );
    while ( my $line = <FH> ) {
        print $line;
    }
    close( FH );
}

sub test_switch {
    my $id = shift;

    switch( $id ) {
      case 'add' { print 'aa' };
    }

    return 1;
}

##</code><code>##

GLOB(0x98dfbdc)
111

##</code><code>##

use Switch;
and
sub test_switch { ... }

##</code><code>##

111
111

##</code><code>##

$ perl -MO=Deparse test.pl

...
die "Error: $!" unless open my $fh, '<', '/tmp/test_file.txt';
use File::Glob ();
while (defined( my $line = glob( ' ' . $fh ))) {
    print "$line\n";
}
close $fh