How to find unused images in an Xcode project?

Question

Has anyone a one-line to find unused images in an Xcode project? (Assuming all the files are referenced by name in code or the project files - no code generated file names.)

Answer 1

I made a very slight modification to the excellent answer provided by @EdMcManus to handle projects utilizing asset catalogs.

#!/bin/bash

for i in `find . -name "*.imageset"`; do
    file=`basename -s .imageset "$i"`
    result=`ack -i "$file" --ignore-dir="*.xcassets"`
    if [ -z "$result" ]; then
        echo "$i"
    fi
done

I don't really write bash scripts, so if there are improvements to be made here (likely) let me know in the comments and I'll update it.