Isn't my code only calling cryptText (my encrypt sub) one time?

No, once for each element in @$input.

foreach my $text (@$input) {
   ...
   $text = encrypt($text,$key);
   ...
}
[download]

Alright thanks. Gonna be pretty busy over the next few days, but ill modify my code and post back my results at some point.

Thanks, I have fixed the problem with the following code:

#!/usr/bin/perl -w
use strict;
use warnings;
use Crypt::Tea;

if (@ARGV != 3)
{
        print STDERR "Usage: $0 [-d|-e] [FILENAME] [KEY] \n";
        exit 1;
}

if (($ARGV[0] ne '-d') && ($ARGV[0] ne '-e'))
{
        print "Specify '-d' to decrypt or '-e' to encrypt\n";
  exit 1;
}

my ($action, $file, $key) = @ARGV;

my $input;
{
  open (my $fh, '<', $file) or die $!;
  binmode($fh);
  local $/;
  $input = <$fh>;
}
if ($action eq '-e')
{
  print encrypt($input,$key);
}

if ($action eq '-d')
{
  print decrypt($input,$key);
}
[download]

Can someone explain the "my $input; { ... }" part. I am unfamiliar with this type of code. Is this shorthand for a function?

Just like all the other curlies in your code, { ... } creates a lexical scope. This causes $fh to be freed when we're done with it and causes $/ to revert to its previous value once we're done with it.