Match a single character in a string bash script

Question

My issues is that I want to read a character from the stdin and compare it with a string value. If that character exists then I want to display a message. Eg, saving % into the variable $a:

$ read a % $echo $a % 

There is variable defined say v='~`!@#$%^&*()_-+=:;{[}]|\/<>,."' all possible special character including single tick '

I need to check if the character input exists in the string value. How can I do this.

Answer 1

case $v in *"$a"*) printf '<%s> is in <%s>\n' "$a" "$v" esac 

Answer 2

Here you go:

#!/bin/bash v='~`!@#$%^&*()_-+=:;{[}]|/<>,."' echo type any character and press enter IFS= read -r a [[ $v =~ "$a" ]] && echo match || echo not 

Answer 3

Try this

cat | egrep -e '[~`!@#$%^&*()_-+=:;{[}]|/<>,."]'