1. The problem statement, all variables and given/known data I have a really basic task in which I have to make a shell script, pipe ls to grep and only output files that has capitals in it, meaning no lower case, no symbols, no numbers, etc. I've been searching all over google and my notes but I've been doing this over an hour and still cant figure it out 2. Relevant equations None. 3. The attempt at a solution I tried ls | grep [A-Z][^a-z0-9] but it prints words with symbol such as "_" eg: "DAFA_FDSA".