Shell script: search in specified location for files containing a string inside (not case sensitive)

find-inside.sh

#!/bin/zsh

# Written by: VerityJ
# Published on: https://gist.github.com/verityj
#
# Usage: ./find-inside.sh location search-string
# location should not end in /*
# search-string does not need " or *
#
# Output: file names that contain the search-string inside

if [ -z "$2" ]
then
    echo "Usage: ./find-inside.sh <location> <search-string>  (note: no need for \" or *)"
    echo "<location> example: ~ (user home) or . (current directory)"
    exit 0
fi

printf "\nSearching in '$1/*' for \"$2\" (case-insensitive) ...\n\n"

grep -lir "$2" "$1"/*

# -l outputs file name list
# -i ignore case
# -r recursive search