cat in asm/ cat --show-all option
 

I'm rewriting cat in assembly, primarily to get better at asm, partially to make cat 50% smaller (or at least thats my goal, but cat is about 21000 bytes, it shouldn't be hard). Heres my questions. What exactly does the -A, --show-all option do? From what I can see, it just shows $ on new lines and ^I on every filled line. What exactly is this? I'm sure appending these values would not create the desired effect. Thanks in advance.

It basically shows control characters in the file using common notation ($ for EOL, ^? otherwise). You can 'man cat' for the details.