(2)    For example,

use strict;
#
# K. Yue
# Suggested Solution to Q2, HW#1, CSCI 4230, Summer 2001
#
my $filename = "words.txt";
open(IN, "<$filename") or die "Can't open file $filename";

print "All words from the dictionary $filename that are also words if the last character is removed.\n\n";
my %words = ();
my $temp = "";
while ($_ = <IN>) {
    chomp;
    $_ = lc $_;
    $temp = $_;
    chop $temp;
    print "$_\n" if $words{$temp};
    $words{$_}++;
}
exit 0;

(3)    For example,

perl -ne "chop; print qq($1: ) if /<document_url>(.*?)<\/document_url>/; print qq($1.\n) if /<harvest_time>(.*?)<\/harvest_time>/;" news.xml