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index db563127b236757de62be50a4e04439eddf2729e..79884d9c74d3175e179dc5a83e9163908242d6ca 100644 (file)
$ man git-diff
------------------------------------------------
+It is a good idea to introduce yourself to git before doing any
+operation. The easiest way to do so is:
+
+------------------------------------------------
+$ cat >~/.gitconfig <<\EOF
+[user]
+ name = Your Name Comes Here
+ email = you@yourdomain.example.com
+EOF
+------------------------------------------------
+
+
Importing a new project
-----------------------
Git will reply
------------------------------------------------
-defaulting to local storage area
+Initialized empty Git repository in .git/
------------------------------------------------
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 with
+every file under the current directory with (notice the dot '.'
+that means the current directory):
------------------------------------------------
$ git add .
Finally,
------------------------------------------------
-$ git commit -a
+$ git commit
------------------------------------------------
will prompt you for a commit message, then record the current state
$ git diff
------------------------------------------------
-to review your changes. When you're done,
+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:
------------------------------------------------
-$ git commit -a
+$ git add file1 file...
+$ git commit
------------------------------------------------
-will again prompt your for a message describing the change, and then
-record the new versions of the modified files.
+This will again prompt your for a message describing the change, and then
+record the new versions of the files you listed. It is cumbersome
+to list all files and you can say `git commit -a` (which stands for 'all')
+instead of running `git add` beforehand.
+
+------------------------------------------------
+$ git commit -a
+------------------------------------------------
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
+example, use the first line on the Subject: line and the rest of the
commit in the body.
-To add a new file, first create the file, then
-------------------------------------------------
-$ git add path/to/new/file
-------------------------------------------------
+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'.
+
-then commit as usual. No special command is required when removing a
-file; just remove it, then commit.
+Viewing the changelog
+---------------------
At any point you can view the history of your changes using
$ git log -p
------------------------------------------------
+Often the overview of the change is useful to get a feel of
+each step
+
+------------------------------------------------
+$ git log --stat --summary
+------------------------------------------------
+
Managing branches
-----------------
------------------------------------------------
at this point the two branches have diverged, with different changes
-made in each. To merge the changes made in the two branches, run
+made in each. To merge the changes made in experimental into master, run
------------------------------------------------
$ git pull . experimental
will show a nice graphical representation of the resulting history.
+At this point you could delete the experimental branch with
+
+------------------------------------------------
+$ git branch -d experimental
+------------------------------------------------
+
+This command ensures that the changes in the experimental branch are
+already in the current branch.
+
If you develop on a branch crazy-idea, then regret it, you can always
delete the branch with
------------------------------------------------
$ cd /home/alice/project
-$ git pull /home/bob/myrepo
+$ git pull /home/bob/myrepo master
------------------------------------------------
-This actually pulls changes from the branch in Bob's repository named
-"master". Alice could request a different branch by adding the name
-of the branch to the end of the git pull command line.
+This merges the changes from Bob's "master" branch into Alice's
+current branch. If Alice has made her own changes in the meantime,
+then she may need to manually fix any conflicts. (Note that the
+"master" argument in the above command is actually unnecessary, as it
+is the default.)
-This merges Bob's changes into her repository; "git log" will
-now show the new commits. If Alice has made her own changes in the
-meantime, then Bob's changes will be merged in, and she will need to
-manually fix any conflicts.
+The "pull" command thus performs two operations: it fetches changes
+from a remote branch, then merges them into the current branch.
-A more cautious Alice might wish to examine Bob's changes before
-pulling them. She can do this by creating a temporary branch just
-for the purpose of studying Bob's changes:
+You can perform the first operation alone using the "git fetch"
+command. For example, Alice could create a temporary branch just to
+track Bob's changes, without merging them with her own, using:
-------------------------------------
$ git fetch /home/bob/myrepo master:bob-incoming
-------------------------------------
which fetches the changes from Bob's master branch into a new branch
-named bob-incoming. (Unlike git pull, git fetch just fetches a copy
-of Bob's line of development without doing any merging). Then
+named bob-incoming. Then
-------------------------------------
$ git log -p master..bob-incoming
shows a list of all the changes that Bob made since he branched from
Alice's master branch.
-After examining those changes, and possibly fixing things, Alice can
-pull the changes into her master branch:
+After examining those changes, and possibly fixing things, Alice
+could pull the changes into her master branch:
-------------------------------------
$ git checkout master
The last command is a pull from the "bob-incoming" branch in Alice's
own repository.
+Alice could also perform both steps at once with:
+
+-------------------------------------
+$ git pull /home/bob/myrepo master:bob-incoming
+-------------------------------------
+
+This is just like the "git pull /home/bob/myrepo master" that we saw
+before, except that it also stores the unmerged changes from bob's
+master branch in bob-incoming before merging them into Alice's
+current branch. Note that git pull always merges into the current
+branch, regardless of what else is given on the commandline.
+
Later, Bob can update his repo with Alice's latest changes using
-------------------------------------
Note that he doesn't need to give the path to Alice's repository;
when Bob cloned Alice's repository, git stored the location of her
-repository in the file .git/remotes/origin, and that location is used
-as the default for pulls.
-
-Bob may also notice a branch in his repository that he didn't create:
+repository in the repository configuration, and that location is
+used for pulls:
-------------------------------------
-$ git branch
-* master
- origin
+$ git repo-config --get remote.origin.url
+/home/bob/myrepo
-------------------------------------
-The "origin" branch, which was created automatically by "git clone",
-is a pristine copy of Alice's master branch; Bob should never commit
-to it.
+(The complete configuration created by git-clone is visible using
+"git repo-config -l", and the gitlink:git-repo-config[1] man page
+explains the meaning of each option.)
+
+Git also keeps a pristine copy of Alice's master branch under the
+name "origin/master":
+
+-------------------------------------
+$ git branch -r
+ origin/master
+-------------------------------------
If Bob later decides to work from a different host, he can still
perform clones and pulls using the ssh protocol:
$ git show c82a22c39cbc32576f64f5c6b3f24b99ea8149c7
-------------------------------------
-But there other ways to refer to commits. You can use any initial
+But there are other ways to refer to commits. You can use any initial
part of the name that is long enough to uniquely identify the commit:
-------------------------------------
$ git show experimental # the tip of the "experimental" branch
-------------------------------------
-Every commit has at least one "parent" commit, which points to the
-previous state of the project:
+Every commit usually has one "parent" commit
+which points to the previous state of the project:
-------------------------------------
$ git show HEAD^ # to see the parent of HEAD
$ git branch stable v2.5 # start a new branch named "stable" based
# at v2.5
$ git reset --hard HEAD^ # reset your current branch and working
- # directory its state at HEAD^
+ # directory to its state at HEAD^
-------------------------------------
Be careful with that last command: in addition to losing any changes
$ git diff v2.5:Makefile HEAD:Makefile.in
-------------------------------------
-You can also use "git cat-file -p" to see any such file:
+You can also use "git show" to see any such file:
-------------------------------------
-$ git cat-file -p v2.5:Makefile
+$ git show v2.5:Makefile
-------------------------------------
Next Steps