Category: Git

Git: How to automatically add the branch name to the end of every commit message

Today I learned… that git can be customized in a number of ways by using its hooks!

On my engineering team, it’s our convention to name feature branches after their corresponding JIRA issues. Likewise, we include the branch (issue) name in every commit message.

$ git commit -m "Fixed the thingy jira/story/ourproject-4555"

Including the branch name / issue name like this means the commit will show up in JIRA linked from the issue itself! Pretty cool. I’ve worked with JIRA a lot over the years, but I’ve never been on a team that actually integrates it with git like this, and the organizational benefits are worth the extra effort.

Alas, it is all too easy to forget to add the branch name at the end of a commit, and I got tired of amending my git messages (which is easy enough: git commit –amend will do it). I knew there had to be a way to automate this.

Adding a git hook

  1. Go into your project’s repo
  2. Open ./git/hooks directory (remember, .git is a hidden directory by default)
  3. Make a copy of .git/hooks/prepare-commit-msg.sample, paste it into the same folder, and remove the .sample extension. You should have a file named simply prepare-commit-msg with no extension.
  4. Paste this into the new file:
# Automatically adds branch name to the end of every commit message.

NAME=$(git branch | grep '*' | sed 's/* //')
echo $(cat "$1") "$NAME" > "$1"

The first line gets the git branch name and sets it to “NAME”.

The second line echoes the contents of your commit message (represented as $1), adds “NAME” to it, and replaces $1 with your message + NAME.

Just save the file and try it out in bash now! No need to reload bash or source anything.

Here’s the gist: 

# Automatically adds branch name to the end of every commit message. Handy for git/JIRA integrations.

# Make a copy of .git/hooks/prepare-commit-msg.sample in your repo and name the file prepare-commit-msg (remove "sample" extension)
# Paste the following into the file, save the file, and try it out in bash

NAME=$(git branch | grep '*' | sed 's/* //') 
echo $(cat "$1") "$NAME" > "$1"

More examples

There are many ways to approach this problem, and you can do a lot of sophisticated things with Git hooks. Here are some resources I found helpful in learning about git hooks and git in general:

Push to GitHub without entering username and password every time (Git Bash on Windows)

Today I learned… how to save my GitHub username and password so I don’t have to re-enter them every time I push something to GitHub from my Windows machine.

A bit of backstory:

I recently set up git on my Windows 7 machine using Git for Windows (mysisgit). That process went smoothly and I feel right at home in my little emulator, Git Bash, using all the same commands I already know and love from my Mac.

If you’re used to using git on a Mac and have to work on a Windows machine for whatever reason, I highly recommend mysisgit.

Credential check… every time!

Everything was going great until I pushed my changes. Every push triggered a new credentials check!

$ git push origin master
Username for 'https://github.com': xyz
Password for 'https://xyz@github.com':

I don’t want to enter my GitHub username and password every time I push something.

HTTPS vs. SSH?

So I hit the Google and found this StackOverflow question, where some helpful folks say the problem results from connecting over HTTPS instead of SSH, but GitHub’s help documentation recommends connecting over HTTPS, not SSH.

I’m hesitant to disobey the word of GitHub, so instead of relying on SSH, I followed GitHub’s instructions to use a credentials helper.

Credentials Helper Setup

However… GitHub’s explanation of how to cache your password with the credentials helper aren’t very clear. They tell you to enter this line and then don’t tell you what to do next.

Here’s what I did – worked for me.

In your Git Bash window, enter this line:

$ git config --global credential.helper wincred

Now push a change to Github and enter your credentials – this is where your username and password information gets saved to the credential helper.

You won’t get any feedback telling you that, but you can confirm it worked by pushing another change. This time, you shouldn’t have to enter your credentials again.

But I have this problem on Linux!

Try this: Caching your GitHub password in Git

$ git config --global credential.helper cache


Quickly add lines to .gitignore using echo in the command line

Today I learned… that you don’t have to open .gitignore in your editor, add a line(s) to it, save it, and close it. You can do all that in one step from the command line using echo!

Here’s a preview:

$ echo '.DS_Store' >> .gitignore

How it works

Here’s a common scenario. You do git status on your working folder and discover git wants to add some file you don’t want added to your remote repository, like the pesky .DS_Store file.

Thanks, but no thanks, git. I don't want that .DS_Store file in my git repository.
Thanks, but no thanks, git. I don’t want that .DS_Store file in my git repository.

If your git project doesn’t already have a .gitignore file, create one in one step by typing this while in your project’s root directory:

$ touch .gitignore

From here, you could open that .gitignore file in an editor and add lines to it, save it and close it, but that’s rather cumbersome if all you need to add is one or a few lines.

Here’s a faster way, using “echo” to push some new data into the file.

$ echo '.DS_Store' >> .gitignore

The double >> is important. If you type just one >, you’ll overwrite the existing contents. Using >> appends your echo string to the end.

For a sanity check, open up .gitignore and you’ll see that .DS_Store has been added.

Once you’re more accustomed to using .gitignore you’ll probably come up with a “boilerplate” .gitignore to copy and paste into all your projects, but you’ll probably never reach a point where you aren’t occasionally surprised by an unwanted file showing up in your git status.