Everyday GIT With 20 Commands Or So
===================================
-GIT suite has over 100 commands, and the manual page for each of
-them discusses what the command does and how it is used in
-detail, but until you know what command should be used in order
-to achieve what you want to do, you cannot tell which manual
-page to look at, and if you know that already you do not need
-the manual.
-
-Does that mean you need to know all of them before you can use
-git? Not at all. Depending on the role you play, the set of
-commands you need to know is slightly different, but in any case
-what you need to learn is far smaller than the full set of
-commands to carry out your day-to-day work. This document is to
-serve as a cheat-sheet and a set of pointers for people playing
-various roles.
-
-<<Basic Repository>> commands are needed by people who has a
+<<Basic Repository>> commands are needed by people who have a
repository --- that is everybody, because every working tree of
git is a repository.
works alone.
If you work with other people, you will need commands listed in
-<<Individual Developer (Participant)>> section as well.
+the <<Individual Developer (Participant)>> section as well.
-People who play <<Integrator>> role need to learn some more
+People who play the <<Integrator>> role need to learn some more
commands in addition to the above.
<<Repository Administration>> commands are for system
-administrators who are responsible to care and feed git
-repositories to support developers.
+administrators who are responsible for the care and feeding
+of git repositories.
Basic Repository[[Basic Repository]]
------------------------------------
-Everybody uses these commands to feed and care git repositories.
+Everybody uses these commands to maintain git repositories.
- * gitlink:git-init-db[1] or gitlink:git-clone[1] to create a
+ * gitlink:git-init[1] or gitlink:git-clone[1] to create a
new repository.
- * gitlink:git-fsck-objects[1] to validate the repository.
+ * gitlink:git-fsck[1] to check the repository for errors.
- * gitlink:git-prune[1] to garbage collect crufts in the
- repository.
+ * gitlink:git-prune[1] to remove unused objects in the repository.
* gitlink:git-repack[1] to pack loose objects for efficiency.
+ * gitlink:git-gc[1] to do common housekeeping tasks such as
+ repack and prune.
+
+Examples
+~~~~~~~~
+
+Check health and remove cruft.::
++
+------------
+$ git fsck <1>
+$ git count-objects <2>
+$ git repack <3>
+$ git gc <4>
+------------
++
+<1> running without `\--full` is usually cheap and assures the
+repository health reasonably well.
+<2> check how many loose objects there are and how much
+disk space is wasted by not repacking.
+<3> without `-a` repacks incrementally. repacking every 4-5MB
+of loose objects accumulation may be a good rule of thumb.
+<4> it is easier to use `git gc` than individual housekeeping commands
+such as `prune` and `repack`. This runs `repack -a -d`.
+
+Repack a small project into single pack.::
++
+------------
+$ git repack -a -d <1>
+$ git prune
+------------
++
+<1> pack all the objects reachable from the refs into one pack,
+then remove the other packs.
+
+
Individual Developer (Standalone)[[Individual Developer (Standalone)]]
----------------------------------------------------------------------
A standalone individual developer does not exchange patches with
-other poeple, and works alone in a single repository, using the
+other people, and works alone in a single repository, using the
following commands.
* gitlink:git-show-branch[1] to see where you are.
* gitlink:git-log[1] to see what happened.
- * gitlink:git-whatchanged[1] to find out where things have
- come from.
-
* gitlink:git-checkout[1] and gitlink:git-branch[1] to switch
branches.
- * gitlink:git-add[1] and gitlink:git-update-index[1] to manage
- the index file.
+ * gitlink:git-add[1] to manage the index file.
* gitlink:git-diff[1] and gitlink:git-status[1] to see what
you are in the middle of doing.
* gitlink:git-reset[1] and gitlink:git-checkout[1] (with
pathname parameters) to undo changes.
- * gitlink:git-pull[1] with "." as the remote to merge between
- local branches.
+ * gitlink:git-merge[1] to merge between local branches.
* gitlink:git-rebase[1] to maintain topic branches.
+ * gitlink:git-tag[1] to mark known point.
Examples
~~~~~~~~
-* Extract a tarball and create a working tree and a new repository to keep track of it.
+Use a tarball as a starting point for a new repository.::
++
------------
$ tar zxf frotz.tar.gz
$ cd frotz
-$ git-init-db
-$ git add .
+$ git-init
+$ git add . <1>
$ git commit -m 'import of frotz source tree.'
+$ git tag v2.43 <2>
------------
++
+<1> add everything under the current directory.
+<2> make a lightweight, unannotated tag.
-* Create a topic branch and develop
+Create a topic branch and develop.::
++
------------
-$ git checkout -b private
+$ git checkout -b alsa-audio <1>
$ edit/compile/test
-$ git diff <1>
-$ git checkout -- foo.c <2>
+$ git checkout -- curses/ux_audio_oss.c <2>
+$ git add curses/ux_audio_alsa.c <3>
$ edit/compile/test
-$ git commit -a -s <3>
-$ git checkout master <4>
-$ git pull . private <5>
-
-<1> to see what changes you are committing.
-<2> revert your botched changes in selected path "foo.c".
-<3> commit everything as you have tested.
-<4> switch to the master branch.
-<5> merge a topic branch into your master branch
+$ git diff HEAD <4>
+$ git commit -a -s <5>
+$ edit/compile/test
+$ git reset --soft HEAD^ <6>
+$ edit/compile/test
+$ git diff ORIG_HEAD <7>
+$ git commit -a -c ORIG_HEAD <8>
+$ git checkout master <9>
+$ git merge alsa-audio <10>
+$ git log --since='3 days ago' <11>
+$ git log v2.43.. curses/ <12>
------------
++
+<1> create a new topic branch.
+<2> revert your botched changes in `curses/ux_audio_oss.c`.
+<3> you need to tell git if you added a new file; removal and
+modification will be caught if you do `git commit -a` later.
+<4> to see what changes you are committing.
+<5> commit everything as you have tested, with your sign-off.
+<6> take the last commit back, keeping what is in the working tree.
+<7> look at the changes since the premature commit we took back.
+<8> redo the commit undone in the previous step, using the message
+you originally wrote.
+<9> switch to the master branch.
+<10> merge a topic branch into your master branch.
+<11> review commit logs; other forms to limit output can be
+combined and include `\--max-count=10` (show 10 commits),
+`\--until=2005-12-10`, etc.
+<12> view only the changes that touch what's in `curses/`
+directory, since `v2.43` tag.
Individual Developer (Participant)[[Individual Developer (Participant)]]
learn how to communicate with others, and uses these commands in
addition to the ones needed by a standalone developer.
- * gitlink:git-pull[1] from "origin" to keep up-to-date with
- the upstream.
+ * gitlink:git-clone[1] from the upstream to prime your local
+ repository.
+
+ * gitlink:git-pull[1] and gitlink:git-fetch[1] from "origin"
+ to keep up-to-date with the upstream.
- * gitlink:git-push[1] to shared repository if you adopt CVS
+ * gitlink:git-push[1] to shared repository, if you adopt CVS
style shared repository workflow.
* gitlink:git-format-patch[1] to prepare e-mail submission, if
you adopt Linux kernel-style public forum workflow.
-
Examples
~~~~~~~~
-* Clone the upstream and work on it. Feed changes to upstream.
+Clone the upstream and work on it. Feed changes to upstream.::
++
------------
$ git clone git://git.kernel.org/pub/scm/.../torvalds/linux-2.6 my2.6
$ cd my2.6
$ edit/compile/test; git commit -a -s <1>
-$ git format-patch master <2>
+$ git format-patch origin <2>
$ git pull <3>
-$ git pull git://git.kernel.org/pub/.../jgarzik/libata-dev.git ALL <4>
-
+$ git log -p ORIG_HEAD.. arch/i386 include/asm-i386 <4>
+$ git pull git://git.kernel.org/pub/.../jgarzik/libata-dev.git ALL <5>
+$ git reset --hard ORIG_HEAD <6>
+$ git prune <7>
+$ git fetch --tags <8>
+------------
++
<1> repeat as needed.
<2> extract patches from your branch for e-mail submission.
-<3> "pull" fetches from "origin" by default and merges.
-<4> fetch from a specific branch from a specific repository and and merge.
+<3> `git pull` fetches from `origin` by default and merges into the
+current branch.
+<4> immediately after pulling, look at the changes done upstream
+since last time we checked, only in the
+area we are interested in.
+<5> fetch from a specific branch from a specific repository and merge.
+<6> revert the pull.
+<7> garbage collect leftover objects from reverted pull.
+<8> from time to time, obtain official tags from the `origin`
+and store them under `.git/refs/tags/`.
+
+
+Push into another repository.::
++
------------
-
-* Branch off of a specific tag.
+satellite$ git clone mothership:frotz frotz <1>
+satellite$ cd frotz
+satellite$ git config --get-regexp '^(remote|branch)\.' <2>
+remote.origin.url mothership:frotz
+remote.origin.fetch refs/heads/*:refs/remotes/origin/*
+branch.master.remote origin
+branch.master.merge refs/heads/master
+satellite$ git config remote.origin.push \
+ master:refs/remotes/satellite/master <3>
+satellite$ edit/compile/test/commit
+satellite$ git push origin <4>
+
+mothership$ cd frotz
+mothership$ git checkout master
+mothership$ git merge satellite/master <5>
+------------
++
+<1> mothership machine has a frotz repository under your home
+directory; clone from it to start a repository on the satellite
+machine.
+<2> clone sets these configuration variables by default.
+It arranges `git pull` to fetch and store the branches of mothership
+machine to local `remotes/origin/*` tracking branches.
+<3> arrange `git push` to push local `master` branch to
+`remotes/satellite/master` branch of the mothership machine.
+<4> push will stash our work away on `remotes/satellite/master`
+tracking branch on the mothership machine. You could use this as
+a back-up method.
+<5> on mothership machine, merge the work done on the satellite
+machine into the master branch.
+
+Branch off of a specific tag.::
++
------------
$ git checkout -b private2.6.14 v2.6.14 <1>
$ edit/compile/test; git commit -a
$ git checkout master
$ git format-patch -k -m --stdout v2.6.14..private2.6.14 |
git am -3 -k <2>
+------------
++
<1> create a private branch based on a well known (but somewhat behind)
tag.
-<2> forward port all changes in private2.6.14 branch to master
-branch without formal "merging".
-------------
+<2> forward port all changes in `private2.6.14` branch to `master` branch
+without a formal "merging".
Integrator[[Integrator]]
* gitlink:git-push[1] to publish the bleeding edge.
+Examples
+~~~~~~~~
+
+My typical GIT day.::
++
+------------
+$ git status <1>
+$ git show-branch <2>
+$ mailx <3>
+& s 2 3 4 5 ./+to-apply
+& s 7 8 ./+hold-linus
+& q
+$ git checkout -b topic/one master
+$ git am -3 -i -s -u ./+to-apply <4>
+$ compile/test
+$ git checkout -b hold/linus && git am -3 -i -s -u ./+hold-linus <5>
+$ git checkout topic/one && git rebase master <6>
+$ git checkout pu && git reset --hard next <7>
+$ git merge topic/one topic/two && git merge hold/linus <8>
+$ git checkout maint
+$ git cherry-pick master~4 <9>
+$ compile/test
+$ git tag -s -m 'GIT 0.99.9x' v0.99.9x <10>
+$ git fetch ko && git show-branch master maint 'tags/ko-*' <11>
+$ git push ko <12>
+$ git push ko v0.99.9x <13>
+------------
++
+<1> see what I was in the middle of doing, if any.
+<2> see what topic branches I have and think about how ready
+they are.
+<3> read mails, save ones that are applicable, and save others
+that are not quite ready.
+<4> apply them, interactively, with my sign-offs.
+<5> create topic branch as needed and apply, again with my
+sign-offs.
+<6> rebase internal topic branch that has not been merged to the
+master, nor exposed as a part of a stable branch.
+<7> restart `pu` every time from the next.
+<8> and bundle topic branches still cooking.
+<9> backport a critical fix.
+<10> create a signed tag.
+<11> make sure I did not accidentally rewind master beyond what I
+already pushed out. `ko` shorthand points at the repository I have
+at kernel.org, and looks like this:
++
+------------
+$ cat .git/remotes/ko
+URL: kernel.org:/pub/scm/git/git.git
+Pull: master:refs/tags/ko-master
+Pull: next:refs/tags/ko-next
+Pull: maint:refs/tags/ko-maint
+Push: master
+Push: next
+Push: +pu
+Push: maint
+------------
++
+In the output from `git show-branch`, `master` should have
+everything `ko-master` has, and `next` should have
+everything `ko-next` has.
+
+<12> push out the bleeding edge.
+<13> push the tag out, too.
+
+
Repository Administration[[Repository Administration]]
------------------------------------------------------
* gitlink:git-shell[1] can be used as a 'restricted login shell'
for shared central repository users.
- * link:howto/update-hook-example.txt[update hook howto] has a
- good example of managing a shared central repository.
+link:howto/update-hook-example.txt[update hook howto] has a good
+example of managing a shared central repository.
+
+
+Examples
+~~~~~~~~
+We assume the following in /etc/services::
++
+------------
+$ grep 9418 /etc/services
+git 9418/tcp # Git Version Control System
+------------
+
+Run git-daemon to serve /pub/scm from inetd.::
++
+------------
+$ grep git /etc/inetd.conf
+git stream tcp nowait nobody \
+ /usr/bin/git-daemon git-daemon --inetd --export-all /pub/scm
+------------
++
+The actual configuration line should be on one line.
+
+Run git-daemon to serve /pub/scm from xinetd.::
++
+------------
+$ cat /etc/xinetd.d/git-daemon
+# default: off
+# description: The git server offers access to git repositories
+service git
+{
+ disable = no
+ type = UNLISTED
+ port = 9418
+ socket_type = stream
+ wait = no
+ user = nobody
+ server = /usr/bin/git-daemon
+ server_args = --inetd --export-all --base-path=/pub/scm
+ log_on_failure += USERID
+}
+------------
++
+Check your xinetd(8) documentation and setup, this is from a Fedora system.
+Others might be different.
+Give push/pull only access to developers.::
++
+------------
+$ grep git /etc/passwd <1>
+alice:x:1000:1000::/home/alice:/usr/bin/git-shell
+bob:x:1001:1001::/home/bob:/usr/bin/git-shell
+cindy:x:1002:1002::/home/cindy:/usr/bin/git-shell
+david:x:1003:1003::/home/david:/usr/bin/git-shell
+$ grep git /etc/shells <2>
+/usr/bin/git-shell
+------------
++
+<1> log-in shell is set to /usr/bin/git-shell, which does not
+allow anything but `git push` and `git pull`. The users should
+get an ssh access to the machine.
+<2> in many distributions /etc/shells needs to list what is used
+as the login shell.
+
+CVS-style shared repository.::
++
+------------
+$ grep git /etc/group <1>
+git:x:9418:alice,bob,cindy,david
+$ cd /home/devo.git
+$ ls -l <2>
+ lrwxrwxrwx 1 david git 17 Dec 4 22:40 HEAD -> refs/heads/master
+ drwxrwsr-x 2 david git 4096 Dec 4 22:40 branches
+ -rw-rw-r-- 1 david git 84 Dec 4 22:40 config
+ -rw-rw-r-- 1 david git 58 Dec 4 22:40 description
+ drwxrwsr-x 2 david git 4096 Dec 4 22:40 hooks
+ -rw-rw-r-- 1 david git 37504 Dec 4 22:40 index
+ drwxrwsr-x 2 david git 4096 Dec 4 22:40 info
+ drwxrwsr-x 4 david git 4096 Dec 4 22:40 objects
+ drwxrwsr-x 4 david git 4096 Nov 7 14:58 refs
+ drwxrwsr-x 2 david git 4096 Dec 4 22:40 remotes
+$ ls -l hooks/update <3>
+ -r-xr-xr-x 1 david git 3536 Dec 4 22:40 update
+$ cat info/allowed-users <4>
+refs/heads/master alice\|cindy
+refs/heads/doc-update bob
+refs/tags/v[0-9]* david
+------------
++
+<1> place the developers into the same git group.
+<2> and make the shared repository writable by the group.
+<3> use update-hook example by Carl from Documentation/howto/
+for branch policy control.
+<4> alice and cindy can push into master, only bob can push into doc-update.
+david is the release manager and is the only person who can
+create and push version tags.
+
+HTTP server to support dumb protocol transfer.::
++
+------------
+dev$ git update-server-info <1>
+dev$ ftp user@isp.example.com <2>
+ftp> cp -r .git /home/user/myproject.git
+------------
++
+<1> make sure your info/refs and objects/info/packs are up-to-date
+<2> upload to public HTTP server hosted by your ISP.