Pass node index into command interpreter with specified options

You need to use 2 mandatory options with arguments:

• Shift

Points out how much letters will replace down if value is positive or replace up if negative;

--shift <value> or -s <value>

examples:

node index --shift 7

node index -s -3

• Action

Pass 'encode' to encrypt message or 'decode' vice versa

--action <value> or -a <value>

exmaples:

node index --action encode

node index -a decode

Also you can you use 2 additional options:

• Input

Tells program where obtain source string. Input value should be file with .txt extension. If doesn't specified program will recive input from process input stream.

node index --input <sourceFile>

exmaples:

node index --input source.txt

node index -i ./folder/source.txt

• Output

Tells program where obtain source string. Input value should be file with .txt extension. If doesn't specified program will dispatch output value to process output stream.

node index --output <distFile>

exmaples:

node index --output dist.txt

node index -o ./folder/dist.txt

Create new encrypted message from index.txt file and wirite it to output.txt with shift 7.

node index -a encode -s 7 -i "./input.txt" -o "./output.txt"

input.txt

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

output.txt

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