rot.pl

#!/usr/bin/perl
## Example from http://langref.org/all-languages/strings/reversing-a-string/simple-substitution-cipher

sub rot13 {
  my $str = shift;
  $str =~ tr/A-Za-z/N-ZA-Mn-za-m/;
  return $str;
}

sub rot47 {
  my $str = shift;
  $str =~ tr/!-~/P-~!-O/;
  return $str;
}

# Original string.
$original = 'Hello World #123';

# Cypher the string.
$weird = rot47($original);
print "$weird\n";

# Decypher the string back again;
$normalized = rot47($weird);
print "$normalized\n";

## It is possible to do some cool transformation in the terminal using
## the technique. Example:
# $ echo 'w6==@ (@C=5 R`ab' | perl -pe 'tr/P-~!-O/!-~/'
# Hello World #123