System level programming

Using the terminal

1. Write a program that takes a key (a number from 1 to 26) an input file name, and an output file name from the command line and uses the key to encrypt it with a Caesar cipher. A Caesar cipher performs modular addition of the key and the letter. If the key is 1 then a>b, b->c, .., y->z, z->a. Ignore all the things that aren't the letters from a to z (simply pass them through) and you will want to put the letters into lower case. Use the too.) file messagel.txt and a key of 7 to encrypt it. (You can do this one pretty easily in bash