#!/usr/bin/perl

use Getopt::Long;

# Set default options
sub usage {
    return " Usage: $0 [line1] [line2] [file]\n\n"
	. " This shows from [line1] to [line2] of a file.\n\n"
	. " Optional arguments: \n"
	. " -h        Print this message\n";
}
my $help;
GetOptions("h" => \$help, "help" => \$help);

die usage() if ($help);

my $line1= shift;
die "Invalid starting line \"$line1\"\n" unless ($line1 =~ /^\d+$/);
my $line2= shift;
die "Invalid ending line \"$line2\"\n" unless ($line2 =~ /^\d+$/);
die "Ending line \"$line2\" gt starting\n" if ($line1 > $line2);

if ($#ARGV < 1) { # zero or one arguments
    my $file= shift;
    die "Invalid file \"$file\"\n" unless ((-T file) or ($file ne '-'));

    my $diff= $line2 - $line1 + 1;
    exec("head -$line2 $file | tail -$diff");

} else {

    while (@ARGV) {
	my $file= shift;
	die "Invalid file \"$file\"\n" unless ((-T file) or ($file ne '-'));

	my $diff= $line2 - $line1 + 1;
	system("echo \'$file ::\'");
	system("head -$line2 $file | tail -$diff");
    }

}