SCSS compilation pre-commit hook

pre-commit

#!/bin/bash

# When SCSS is changed in a commit, this compiles and commits the affected css.
# This script assumes a project directory of the form:
#     main.scss
#     main.css
#     scss
#       |  file_1.scss
#       |  ...
#       |  file_n.scss
# Where `main.scss` imports other files, and `main.css` is the compiled product.

# The below command is most of the work here. It's complicated, so here's an explanation:
#  * Get a list of all diffed files (various flags to remove frills)
#  * Filter for .scss files
#  * Use `dirname` to get the directory path
#  * If the file is in a "scss" directory, go up one level
#  * Use `uniq` to ensure we're not double counting directories
paths=`git --no-pager diff --cached --name-only --diff-filter=ACM \
       | grep ".scss$" \
       | xargs -L 1 dirname 2>/dev/null \
       | sed 's/\/scss$//' \
       | uniq`
for path in $paths; do
    scss $path/main.scss > $path/main.css
    git add $path/main.css
    echo "Generated and added $path/main.css"
done

exit 0