gistfile1.sh

#!/bin/bash

# This script intends to remove all unused images from the project.
# Use with caution and don't forget to back-up before using.

SRC=./source/images

# Create a `.tmp` folder
mkdir -p .tmp

# List all images from source folder in `./.tmp/img_list` (exclude SVG files)
find $SRC -name '*.gif' -o -name '*.jpg' -o -name '*.png' -o -name '*.jpeg' > ./.tmp/img_list

# List all images used in Markdown files in `./.tmp/used_img_list`
grep --include='*.md' -Ro '!\[[^]]*\]([^)]*)' . | sed 's/[^(]*(//' | grep '^/images/' | sed 's/)$//' | sed 's/^/.\/source/' > ./.tmp/used_img_list

# Sort lists as `.sorted`
sort ./.tmp/img_list > ./.tmp/img_list.sorted && sort ./.tmp/used_img_list > ./.tmp/used_img_list.sorted

# Compare them in `./.tmp/diff` only to keep unused images
comm -23 ./.tmp/img_list.sorted ./.tmp/used_img_list.sorted > ./.tmp/diff

# Remove all unused images from `images` folder
# Unfortunately cannot use `xargs rm < ./.tmp/diff` because of spaces in filenames
cat ./.tmp/diff | while read file; do rm "$file"; done

# Clean possible empty folders
find $SRC -type d -empty -exec rmdir {} \+

# Clean work station
rm -rf ./.tmp