This is a command-line interface to encrypt and decrypt text with Caesar's cipher. The application encrypts and decrypts only latin alphabet letters. All other characters remain unchanged.

1. Download or clone this repository.
2. Run command line and go to the application folder.

In the application folder, enter the following into the command line: "node caesar-cli [options]".

Options:

• -s, --shift: a shift
• -i, --input: an input file
• -o, --output: an output file
• -a, --action: an action encode/decode

The action option is required and can take the values of encode or deconde and indicates what needs to be done with the incoming text: encrypt or decrypt.

The shift option is required and must be an integer (you can also use negative values ​​or values ​​that exceed the length of the alphabet). It denotes a shift of letters for encryption and decryption.

The input option must be relative or absolute path to input file. If there are spaces in the path, it must be wrapped in quotes.

The output option must be relative or absolute path to output file. If there are spaces in the path, it must be wrapped in quotes.

If the input and/or the output options are absent, then reading and writing will be carried out from/to the command line.

Encription with shorthand names of the options

$ node caesar-cli -a encode -s 7 -i ./input.txt -o ./output.txt

Before:

input.txt This is secret. Message about "_" symbol!

output.txt empty

After:

input.txt This is secret. Message about "_" symbol!

output.txt Aopz pz zljyla. Tlzzhnl hivba "_" zftivs!

Decryption with full names of the options

$ node caesar-cli --action decode --shift 7 --input ./plain.txt --output ./decode.txt

Before:

plain.txt Aopz pz zljyla. Tlzzhnl hivba "_" zftivs!

decode.txt empty

After:

plain.txt Aopz pz zljyla. Tlzzhnl hivba "_" zftivs!

decode.txt This is secret. Message about "_" symbol!