#!/usr/bin/perl
# perl-grep4.pl

my $pattern = shift @ARGV;

my $regex = eval { qr/$pattern/ };
die "Check your pattern! $@" if $@;

while( <> )
    {
    if( m/$regex/ )
        {

        print "$_";

        print "\t\t\$&: ",
            substr( $_, $-[0], $+[0] - $-[0] ),
            "\n";

        foreach my $i ( 1 .. $#- )
            {
            print "\t\t\$$i: ",
                substr( $_, $-[$i], $+[$i] - $-[$i] ),
                "\n";
            }
        }
    }