Unix Programming?

Question

Write a shell program to cipher all the text/content in any text document in the current working directory and also use another shell program to decipher it to read. Use any schema for ciphering

Answer 1

I wont write your shell for you but here is a schema

tr a-z n-za-m | tr A-Z N-ZA-M

Rotate 13. It takes the 26 letters in the alphabet and rotates them 13 positions. It "translates" a-z into being n-z and a-m.
So if I typed
echo This is a test | tr a-z n-za-m | tr A-Z N-ZA-M
then I get back
Guvf vf n grfg
and if I want to translate that then I run it thru again
echo Guvf vf n grfg | tr a-z n-za-m|tr A-Z N-ZA-M
then I get
This is a test

Now just write a script that lets you give it a file to encrypt or decript

Answer 2

This question has been posted so many times on here. Hasn't this homework's deadline come and gone yet?