C:\>perl -MO=Deparse,-p
#!usr/bin/env perl

open  (test, "@ARGV");

while (<test>) {
    $_ =~ <test>;
    chomp;
    s/(th)/TH/gi;
    print "$_\n";
}

close (test);
^Z
open(test, "@ARGV");
while (defined(($_ = <test>))) {
    ($_ =~ <test>);
    chomp($_);
    s/(th)/TH/gi;
    print("$_\n");
}
close(test);
- syntax OK