Bash show charcaters if not in string

Question

I am trying out bash, and I am trying to make a simple hangman game now.

Everything is working but I don\'t understand how to do one thing:

I am showing the

Answer 1

You don't show what you tried, but parameter expansion works fine.

$ alphabet=abcdefghijklmnopqrstuvwxyz
$ word="hello world"
$ guesses=aetl
$ echo "${word//[^[:space:]$guesses]/*}"
*ell* ***l*
$ echo "${alphabet//[$guesses]/*}"
*bcd*fghijk*mnopqrs*uvwxyz

Answer 2

First store both strings in files where they are stored one char per line:

sed 's/./&\n/g' | sort <<< $guess > guessfile
sed 's/./&\n/g' | sort <<< $word > wordfile

Then we can filter the words that are only present in one of the files and paste the lines together as a string:

grep -xvf guessfile wordfile | paste -s -d'\0'

And of course we clean up after ourselves:

rm wordfile
rm guessfile

If the output is not correct, try switching arguments in grep (i.e. wordfile guessfile instead of guessfile wordfile).