Teach me git commit

Question

I don’t understand git commit at all.

It’s been a week since I’ve been using git and all these git with –a, -m, new files, untracked etc is making me totally confused. Tortoisegit is saving me for the moment, but I would like to understand the essence and use it in a way it’s totally easy.

When I am in the git command line, it’s rather difficult to selectively commit some files and keep the rest for another commit. How do I make this easy?

Answer 1

It is quite simple. You need to add the changes that you want to the index first:

git add file1 file2 

then

git commit 

if you removed a file, the add does that. Add means "add the change" even though it is a removal.

If you want to add all changes:

git add -A 

The -a parameter on commit says to add all changes of tracked files and commit them. So

git commit -a 

will not commit a new file you created. You must explicitly add this.

The -m parameter allows you to avoid opening the editor to edit your commit message and use what you put in following the -m option:

git commit -m "Use this message and don't open the editor" 

Sometimes this is not a good idea. If you just tried a merge and had conflicts, git caches a very nice message for you once you resolve the conflicts and commit. So there a git commit is better.

To selectively add files, use the patch modifier on git add:

git add -p 

This will now prompt you about the files. This is quite powerful as you can also specify parts of files, or alternatively edit what you want to add to the index. A git commit will only add those.

If you want some gui help that is not tortoisegit (avoid windows shell integration), use git gui.

Here is a diagram explaining the index (or staged files):

(from http://progit.org/book/ch2-2.html)

hope this helps.