LIST="some string with a substring you want to match"SOURCE="substring"if echo "$LIST" | grep -q "$SOURCE"; then echo "matched";else echo "no match";fi
You can also compare with wildcards:
if [[ "$LIST" == *"$SOURCE"* ]]
This works in Bash without forking external commands:
function has_substring() { [[ "$1" != "${2/$1/}" ]]}
Example usage:
name="hello/world"if has_substring "$name" "/"then echo "Indeed, $name contains a slash!"fi