Here's a cute little program that will turn a file of text upside-down (sort of): 
#!/usr/bin/perl
use strict;
use warnings;

my @lines;

while(<>){
 push @lines, $_;
}

while(@lines){
 print flip_line(pop @lines);
}

sub flip_line 
{rev_string(join '', map flip_char($_), split //, shift)}

sub rev_string 
{scalar reverse shift}

sub flip_char 
{$_= lc shift; tr/'ahbbmfnnjpdrvutwqgye'/'eyqgwtuvrdpjnnfmbbha'/; $_}

[download]
For example, the file 
some text can be
flipped over using
this script

[download]
becomes 
fdijcs siyf
buisn jano paddilt
aq uec fxaf awos

[download]
Flipping the text back over can be approximated by something like 
./umop-apisdn.pl < test.txt | ./umop-apisdn.pl

[download]
This is approximate because of case changes and because the mapping function I use doesn't invert cleanly (since v and u both man to n, for example).
Note: this idea is not originally mine, I just wrote this implementation. Check out http://poignantguide.net/ruby/chapter-7.html for the inspiration.
~dewey

In reply to Turning text umop-apisdn by dewey

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