-A tutorial introduction to git
-==============================
+A tutorial introduction to git (for version 1.5.1 or newer)
+===========================================================
This tutorial explains how to import a new project into git, make
changes to it, and share changes with other developers.
+If you are instead primarily interested in using git to fetch a project,
+for example, to test the latest version, you may prefer to start with
+the first two chapters of link:user-manual.html[The Git User's Manual].
+
First, note that you can get documentation for a command such as "git
diff" with:
------------------------------------------------
You've now initialized the working directory--you may notice a new
-directory created, named ".git". Tell git that you want it to track
-every file under the current directory (note the '.') with:
+directory created, named ".git".
+
+Next, tell git to take a snapshot of the contents of all files under the
+current directory (note the '.'), with gitlink:git-add[1]:
------------------------------------------------
$ git add .
------------------------------------------------
-Finally,
+This snapshot is now stored in a temporary staging area which git calls
+the "index". You can permanently store the contents of the index in the
+repository with gitlink:git-commit[1]:
------------------------------------------------
$ git commit
------------------------------------------------
-will prompt you for a commit message, then record the current state
-of all the files to the repository.
+This will prompt you for a commit message. You've now stored the first
+version of your project in git.
Making changes
--------------
-Try modifying some files, then run
+Modify some files, then add their updated contents to the index:
------------------------------------------------
-$ git diff
+$ git add file1 file2 file3
------------------------------------------------
-to review your changes. When you're done, tell git that you
-want the updated contents of these files in the commit and then
-make a commit, like this:
+You are now ready to commit. You can see what is about to be committed
+using gitlink:git-diff[1] with the --cached option:
+
+------------------------------------------------
+$ git diff --cached
+------------------------------------------------
+
+(Without --cached, gitlink:git-diff[1] 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 gitlink:git-status[1]:
+
+------------------------------------------------
+$ 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 add file1 file2 file3
$ git commit
------------------------------------------------
This will again prompt your for a message describing the change, and then
-record the new versions of the files you listed.
+record a new version of the project.
Alternatively, instead of running `git add` beforehand, you can use
$ git commit -a
------------------------------------------------
-which will automatically notice modified (but not new) files.
+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)
example, use the first line on the Subject: line and the rest of the
commit in the body.
-
Git tracks content not files
----------------------------
-With git you have to explicitly "add" all the changed _content_ you
-want to commit together. This can be done in a few different ways:
-
-1) By using 'git add <file_spec>...'
-
-This can be performed multiple times before a commit. Note that this
-is not only for adding new files. Even modified files must be
-added to the set of changes about to be committed. The "git status"
-command gives you a summary of what is included so far for the
-next commit. When done you should use the 'git commit' command to
-make it real.
-
-Note: don't forget to 'add' a file again if you modified it after the
-first 'add' and before 'commit'. Otherwise only the previous added
-state of that file will be committed. This is because git tracks
-content, so what you're really 'add'ing to the commit is the *content*
-of the file in the state it is in when you 'add' it.
-
-2) By using 'git commit -a' directly
-
-This is a quick way to automatically 'add' the content from all files
-that were modified since the previous commit, and perform the actual
-commit without having to separately 'add' them beforehand. This will
-not add content from new files i.e. files that were never added before.
-Those files still have to be added explicitly before performing a
-commit.
-
-But here's a twist. If you do 'git commit <file1> <file2> ...' then only
-the changes belonging to those explicitly specified files will be
-committed, entirely bypassing the current "added" changes. Those "added"
-changes will still remain available for a subsequent commit though.
-
-However, for normal usage you only have to remember 'git add' + 'git commit'
-and/or 'git commit -a'.
-
+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.
Viewing the changelog
---------------------
Be careful with that last command: in addition to losing any changes
in the working directory, it will also remove all later commits from
this branch. If this branch is the only branch containing those
-commits, they will be lost. (Also, don't use "git reset" on a
-publicly-visible branch that other developers pull from, as git will
-be confused by history that disappears in this way.)
+commits, they will be lost. Also, don't use "git reset" on a
+publicly-visible branch that other developers pull from, as it will
+force needless merges on other developers to clean up the history.
+If you need to undo changes that you have pushed, use gitlink:git-revert[1]
+instead.
The git grep command can search for strings in any version of your
project, so
database, the index file, and a few other odds and ends that you'll
need to make the most of git.
-If you don't want to consider with that right away, a few other
+If you don't want to continue with that right away, a few other
digressions that may be interesting at this point are:
* gitlink:git-format-patch[1], gitlink:git-am[1]: These convert