Although I am the only contributor of my own Github project, I still want my commit message to be tidier.

I wish all the commit messages will follow the pattern like:

[Example]: This is an Example.
[Exercise]: This ia an Exercise.
[Problem]: A problem solved.
[Other]: Maybe a merge commit.

However, I usually remember to follow this pattern after the commit, that’s really disappointed. So I decided to write a simple hook to prevent this kind of Amnesia.

Create commit-msg file

Hooks reside in the .git/hooks directory of every Git repository. And if we go to that directory, we’ll find several example hooks. git:(new-blog) ✗ ll .git/hooks
total 80
-rwxr-xr-x  1 Wenfeng  staff   478B May 21 09:36 applypatch-msg.sample
-rwxr-xr-x  1 Wenfeng  staff   896B May 21 09:36 commit-msg.sample
-rwxr-xr-x  1 Wenfeng  staff   189B May 21 09:36 post-update.sample
-rwxr-xr-x  1 Wenfeng  staff   424B May 21 09:36 pre-applypatch.sample
-rwxr-xr-x  1 Wenfeng  staff   1.6K May 21 09:36 pre-commit.sample
-rwxr-xr-x  1 Wenfeng  staff   1.3K May 21 09:36 pre-push.sample
-rwxr-xr-x  1 Wenfeng  staff   4.8K May 21 09:36 pre-rebase.sample
-rwxr-xr-x  1 Wenfeng  staff   1.2K May 21 09:36 prepare-commit-msg.sample
-rwxr-xr-x  1 Wenfeng  staff   3.5K May 21 09:36 update.sample

So first of all, we create a real commit-msg file in this directory, and make it executable.

cd .git/hooks
touch commit-msg
chmod a+x commit-msg

And here is what I did for the purpose of fixing commit message pattern.


# regex to validate in commit msg

NC='\033[0m' # No Color
error_msg="${RED}Aborting commit. Please follow the commit message pattern \
.${NC}\n[Example|Exercise|Problem|Other]: msg"

if ! grep -qE "$commit_regex" "$1"; then
    echo -e "$error_msg" >&2
    exit 1


Ok, that’s done. It’s not a long story :) Now, if we are not obey the rule, we can’t commit.

algo git:(master) ✗ git commit -m "update gitignore"
Aborting commit. Please follow the commit message pattern .
[Example|Exercise|Problem|Other]: msg

And, if we follow the pattern, we can commit successfully.

algo git:(master) ✗ git commit -m "[Other]: update gitignore"
[master 967773d] [Other]: update gitignore
 1 file changed, 4 insertions(+)

That’s exactly what I want.


I found two links really helpful when creating the commit-msg hook.