Styjun

My intent is to capture the values of a string that I type and have those values be shifted to other letters. Essentially it would be a fake translation program or custom cipher generation script. Example of function:

I would type the sentence:

Who are you?

and the output would be shifted by lets say 1 to the next consonant or vowel, for example. The script would also need to know how to skip vowels or consonants as needed, and for the sake of argument y would always be considered a vowel. So the output would be:

Xju eso auy?

This is something I wanted to attempt for a creative writing project as a means of making another language. Ideally the shift variable could be an input as well to work with to find the best outcome. Possibly even variable shifts for vowels and consonants at the same time?

If you truly are doing this for a creative writing project, then I submit that diving deep into the programming is not warranted. None of the input transformations you described require decisions to be made by the program. That is; once an encoding is chosen, the incoming letters will be each be firmly associated with outgoing letters. This greatly expands your options for how to achieve this, and greatly simplifies the complexity of the task.

Since you tagged Terminal, here are a couple commands you could use in action:

echo "Who are you?" | perl -pe 'tr/N-ZA-Mn-za-m/A-Za-z/'

outputs: Jub ner lbh?

This is the famous Rot13 "encoding" (all it does is substitute the letter that is 13 later in the alphabet). It's particularly handy as 13 is half the alphabet's 26, so putting some "encoded" text in will give you back the original text:

echo "Jub ner lbh?" | perl -pe 'tr/N-ZA-Mn-za-m/A-Za-z/'

outputs: Who are you?
echo just sends text to the screen or other commands. Here we echo our text "How are you?" into a pipe | to pass it to the next command perl, which is a very powerful and flexible text-manipulation and reporting program. The rest of the line is just instructions for perl on how to spin 13 letters later in the alphabet.

Quick note; normally hitting return runs the command in terminal. You can put a backslash at the end of a line though and hit return, it will then let you keep typing on the next line but treat it all as one command. Handy for lining things up.

echo "How are you?" | tr 
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz' 
'DFVBTXEUWZOSHCJMAQYRINKLPGdfvbtxeuwzoshcjmaqyrinklpg'

outputs: Ujk dqt pji?

There's another command, tr. This example demonstrates an arbitrary substitution—in this case, random. It looks through that first long set of letters, and swaps in instead the letter in the second long set that is in the matching position. Since this substitution example is random, you could use this kind of mapping to create "Cryptogram" puzzles.

The great thing about the tr command is that you can tell it to use whatever input-to-output "mapping" you'd like. Sure, it's a bit manual, but hey—no programming needed!

Here's the mapping to achieve your requested "consonants and vowels" example shift:

echo "Who are you?" | tr 
 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz' 
 'ECDFIGHJOKLMNPUQRSTVYWXZABecdfighjoklmnpuqrstvywxzab'

Outputs: Xju esi auy? Not doing it by hand has its advantages—you missed a vowel in there.

So if you need to rapidly try different mappings, consider learning a bit more about perl (or simpler: sed. or more complex: awk. Or or or…). If, instead, you don't mind a bit of careful command-construction, just lining up each incoming letter with your desired output letter, I think tr would serve nicely.