Pre commit git hook. It checks and fails if finds a forbidden pattern like "pdb.set_trace". Will also fail if there's trailing spaces.

pre-commit

#!/bin/sh

if git rev-parse --verify HEAD >/dev/null 2>&1
then
	against=HEAD
else
	# Initial commit: diff against an empty tree object
	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

# Redirect output to stderr.
exec 1>&2

FORBIDDEN_PATTERN='pdb.set_trace'


if ! git diff --cached -S "${FORBIDDEN_PATTERN}" --exit-code HEAD
then
	echo ""
	echo "Error: Found \"${FORBIDDEN_PATTERN}\" references."
	echo "Please, remove them before commiting."
	exit 1
fi

# If there are whitespace errors, print the offending file names and fail.
exec git diff-index --check --cached $against --

git commit option [-n | --no-verify] can be used to bypass this pre-commit hook