Working With Git

Table of Contents

Empty Commit Messages

Why someone may want this is not immediately obvious but the reason is that sometimes a commit doesn’t really require text explaining it. As part of each commit git stores the files that changed and the corresponding changes. This is already more than in enough information in some cases. Where I use this is in the git repo tracking all my configurations. Files like .zshrc, .tmux.conf and a lot of other things in ~/.config. The contents change semi-regularly and having to describe what changed in every commit with a message would be painful. So the solution is the following line in my crontab:

0 */6 * * * cd /home/kajm/.dotfiles && git commit --allow-empty-message -am ''

As you may have already guessed the flag --allow-empty-message is what makes -m '' possible.

Watch Important Files For Changes

This one relies on entr which watches a list of files for changes and does something afterward. There’s a lot of different file watchers but this one in particular I have found to be the most useful. Now since entr takes a file list from stdin means that we can use git ls-files in a repo to watch for changes to only files we have committed. Files that are committed are often the only ones we care about so this is a lot nicer than filtering the output of find or ls. The relevant snippet is:

git ls-files | entr -cr node app.js

Which just reloads a node.js application when the checked in files change. One other task I use this for is regenerating .love files in the background when working on a LÖVE2D game by simply running Make.

(fd -e lua | entr -p make > /dev/null &)

Here I’m using fd as opposed to find because doing things like searching by extension is easier.¹

Saving Online Credentials

Firstly a disclaimer, this method stores your credentials (username + password) in a file .git-credentials in plaintext. This may pose a security issue but if that isn’t really a concern then you’re good to go.

git config credential.helper store

Once you type this, the next time you do an operation that requires entering some credentials (like git pull) they will be saved. If you later want to disable storage remove the credentials file and use:

git config --system --unset credential.helper

Optionally, storing credentials for a short-period is also possible with:

git config --global credential.helper cache

The credentials are kept for a default of 15 minutes but duration can be supplied by changing cache to 'cache --timeout=<seconds>'.

.gitignore Patterns

For the most part the pattern rules are straight-forward but there are some key things to pay attention to:

• The backslash ('\') character is used for escaping e.g for end of line spaces or patterns beginning with a # or !.
• A ! at the beginning of a pattern negates its meaning.
• A leading forward slash does not change the meaning of a pattern that has a forward slash elsewhere in the pattern i.e site/css and /site/css are the same.
• A trailing forward slash on a pattern matches only directories but both files and directories when left out.

Addendum

• You can find templates for .gitignore files here.
• git config --get remote.origin.url prints the remote when run inside a repo you cloned.

Further Reading

• The Credential Storage section of the git book.
• The gitignore documentation section.