#!/usr/bin/perl -w
use strict;
use 5.010;

my ($type, $string);

print "What type of case? (upper/lower):\n";
while (<STDIN>) {
	chomp;
	if (/^(upper|lower)$/i) {
		$type = $_;
		last;
	} else {
		print "Invalid type please type upper or lower:\n";
	}
}

print "Please enter your text:\n";
chomp($string = <STDIN>);
given ($type) {
	when ("upper") { print "\U$string" }
	when ("lower") { print "\L$string" }
}

print "\n";

#!/usr/bin/perl -w
use strict;
use Switch;

my ($input, $type, $string);

print "What type of case? (upper/lower):\n";
while (<STDIN>) {
	chomp;
	if ($_ ne ("upper" || "lower")) {
		print "Invalid type please type upper or lower:\n";
	} else {
		$type = $_;
		last;
	}
}

print "Please enter your text:\n";
chomp($string = <STDIN>);
switch ($type) {
	case "upper" { print uc $string }
	case "lower" { print lc $string }
}

print "\n";

Just run in your consol window as ./tocase (or whatever you call the file). Be sure to give it proper permission first (chmod 755 tocase) :]

Changing text case utility

text

Perl