A Basic Commit

Goals

By the end of this lesson you should be able to…

• Use the git commit command to commit to a repository any changes that were marked with git add
• Add meaningful commit messages to all commits

Commit

You just marked one kind of change in your repository: the addition of a file. The git commit command is used to record changes in your working tree that you have marked with the git add command.

NOTE: In this case there is a single change to commit, but soon you will see that you can commit whole sets of changes in a single commit.

Here is the format for the git commit command:

git commit -m <message>

Commit Messages

Every commit will be annotated with the user name and email set in your Git configuration, plus a commit message which you can specify using the -m option.

NOTE: If you fail to include a commit message using the -m option, Git will open the default command line editor and force you to add a message there. See this note regarding how to set the default editor.

Commit messages should be a brief summary of the changes involved in the commit.

Using meaningful commit message will prove helpful when you are browsing the change history of your repository—you will be able to see at a glance what the changes in each commit achieve.

Do a commit!

$ git commit -m "Initial commit"
[master (root-commit) 17f9667] Initial commit
 1 file changed, 1 insertion(+)
 create mode 100644 git.txt

Note that the commit output gives you:

• a commit ID (17f9667 here, but yours will be different)
• The number files that were changed in the commit
• The number of lines (insertions/deletions) that were changed in the commit
• Which specific files were changed in the commit

Git has now recorded the fact that git.txt was added to the repository. As long as the .git folder remains in your myrepo directory (ie, as long as the myrepo directory remains a Git working tree) you will always be able to go back to this moment and examine how git.txt looked at the time of this commit. You will also be able to compare the differences between any future committed revision of git.txt with this revision.

Before moving on, check the status of your repository once more:

$ git status
On branch master
nothing to commit, working tree clean

Here Git is indicating that the set of files in your working tree are exactly the same as the set of files in the most recent commit of the repository—there are no uncommitted changes and no untracked files in your working tree.

Before moving on, let's spend a bit of time talking about commit IDs…