Git pre-commit hook that fails for changes introducing Jasmine's exclusive tests using "ddescribe" or "iit"

pre-commit

#!/bin/sh
# A git pre-commit hook that verifies that the change does not introduce
# the use of a Jasmine exclusive test via 'iit(..)' or 'ddescribe(..)', which would
# prevent most other tests from being run without any clear indication thereof

# Redirect output to stderr.
exec 1>&2

ADDED_EXCLUSIVE_TEST=$(git diff -U0 --staged -S"(\W|^)(ddescribe|iit))\s+?\(" --pickaxe-regex | egrep "(^\+.*(ddescribe|iit))|\+{3}")

if [ -n "$ADDED_EXCLUSIVE_TEST" ]; then
    echo "PRE-COMIT CHECK FAILED: You have added calls to either iit(..) or ddescribe(..) thus preventing other tests from running, please fix: $ADDED_EXCLUSIVE_TEST"
    exit 1
fi