Normal Workflow
Modify some files, then add their updated contents to the index:
$ git add file1 file2 file3
You are now ready to commit. You can see what is about to be committed using git diff with the --cached option:
$ git diff --cached
(Without --cached, git diff will show you any changes that you've made but not yet added to the index.) You can also get a brief summary of the situation with git status:
$ git status
# On branch master
# Changes to be committed:
# (use "git reset HEAD <file>..." to unstage)
#
# modified: file1
# modified: file2
# modified: file3
#
If you need to make any further adjustments, do so now, and then add any newly modified content to the index. Finally, commit your changes with:
$ git commit
This will again prompt you for a message describing the change, and then record a new version of the project.
Alternatively, instead of running git add beforehand, you can use
$ git commit -a
which will automatically notice any modified (but not new) files, add them to the index, and commit, all in one step.
A note on commit messages: Though not required, it's a good idea to begin the commit message with a single short (less than 50 character) line summarizing the change, followed by a blank line and then a more thorough description. Tools that turn commits into email, for example, use the first line on the Subject: line and the rest of the commit message in the body.
Git tracks content not files
Many revision control systems provide an "add" command that tells the
system to start tracking changes to a new file. Git's "add" command
does something simpler and more powerful: git add is used both for new
and newly modified files, and in both cases it takes a snapshot of the
given files and stages that content in the index, ready for inclusion in
the next commit.
