Select Code to Download

one
two
three

filterTwoThree.pl | oneTwoThree.pl

two 
three

#!c:/perl/bin/perl
#oneTwoThree.pl
...
print "one\n";
print "two\n";
print "three\n";

#filterTwoAndThree.pl
use warnings;
...
if (/two|three/) {
  print $_;
}

perl oneTwoThree.pl | perl -n filterTwoAndThree.pl