git pre-commit hook to check all staged python files for mentioning pdb

pre_commit_breakpoints.sh

# Git pre-commit hook to check all staged python files for mentioning pdb
#
# Installation
#
#   ln -s /path/to/pre-commit_breakpoints.sh /path/to/project/.git/hooks/pre-commit
#
# Based on 
#
#   http://codeinthehole.com/writing/tips-for-using-a-git-pre-commit-hook/
#   http://mark-story.com/posts/view/using-git-commit-hooks-to-prevent-stupid-mistakes
#   https://gist.github.com/3266940
#   https://gist.github.com/3436040

FILES_PATTERN='\.(py)(\..+)?$'
FORBIDDEN="^[#].*pdb"


git diff --cached --name-only --diff-filter=ACM | \
    grep -E $FILES_PATTERN | \
    GREP_COLOR='4;5;37;41' xargs grep --color --with-filename -n $FORBIDDEN && \
    echo 'COMMIT REJECTED bc of breakpoints' && \
    exit 1

exit 0

Fails if there are no python files in the commit.