set_hooks.sh

#!/bin/sh

# Set git pre-commit hook
# REF: https://golang.org/misc/git/pre-commit

cat <<'EOT'> .git/hooks/pre-commit
#!/bin/sh
# Copyright 2012 The Go Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# git gofmt pre-commit hook
#
# To use, store as .git/hooks/pre-commit inside your repository and make sure
# it has execute permissions.
#
# This script does not handle file names that contain spaces.

gofiles=$(git diff --cached --name-only --diff-filter=ACM | grep '\.go$')
[ -z "$gofiles" ] && exit 0

unformatted=$(gofmt -l $gofiles)
[ -z "$unformatted" ] && exit 0

# Some files are not gofmt'd. Print message and fail.

echo >&2 "Go files must be formatted with gofmt. Please run:"
for fn in $unformatted; do
	echo >&2 "  gofmt -w $PWD/$fn"
done

exit 1
EOT

chmod 750 .git/hooks/pre-commit