Everyday GIT With 20 Commands Or So =================================== <<Basic Repository>> commands are needed by people who have a repository --- that is everybody, because every working tree of git is a repository. In addition, <<Individual Developer (Standalone)>> commands are essential for anybody who makes a commit, even for somebody who works alone. If you work with other people, you will need commands listed in the <<Individual Developer (Participant)>> section as well. 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 for the care and feeding of git repositories. Basic Repository[[Basic Repository]] ------------------------------------ Everybody uses these commands to maintain git repositories. * linkgit:git-init[1] or linkgit:git-clone[1] to create a new repository. * linkgit:git-fsck[1] to check the repository for errors. * linkgit: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 gc <3> ------------ + <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> repacks the local repository and performs other housekeeping tasks. Repack a small project into single pack.:: + ------------ $ git gc <1> ------------ + <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 people, and works alone in a single repository, using the following commands. * linkgit:git-show-branch[1] to see where you are. * linkgit:git-log[1] to see what happened. * linkgit:git-checkout[1] and linkgit:git-branch[1] to switch branches. * linkgit:git-add[1] to manage the index file. * linkgit:git-diff[1] and linkgit:git-status[1] to see what you are in the middle of doing. * linkgit:git-commit[1] to advance the current branch. * linkgit:git-reset[1] and linkgit:git-checkout[1] (with pathname parameters) to undo changes. * linkgit:git-merge[1] to merge between local branches. * linkgit:git-rebase[1] to maintain topic branches. * linkgit:git-tag[1] to mark known point. Examples ~~~~~~~~ Use a tarball as a starting point for a new repository.:: + ------------ $ tar zxf frotz.tar.gz $ cd frotz $ 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.:: + ------------ $ git checkout -b alsa-audio <1> $ edit/compile/test $ git checkout -- curses/ux_audio_oss.c <2> $ git add curses/ux_audio_alsa.c <3> $ edit/compile/test $ 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)]] ------------------------------------------------------------------------ A developer working as a participant in a group project needs to learn how to communicate with others, and uses these commands in addition to the ones needed by a standalone developer. * linkgit:git-clone[1] from the upstream to prime your local repository. * linkgit:git-pull[1] and linkgit:git-fetch[1] from "origin" to keep up-to-date with the upstream. * linkgit:git-push[1] to shared repository, if you adopt CVS style shared repository workflow. * linkgit: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.:: + ------------ $ 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 origin <2> $ git pull <3> $ 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 gc <7> $ git fetch --tags <8> ------------ + <1> repeat as needed. <2> extract patches from your branch for e-mail submission. <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.:: + ------------ 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 a formal "merging". Integrator[[Integrator]] ------------------------ A fairly central person acting as the integrator in a group project receives changes made by others, reviews and integrates them and publishes the result for others to use, using these commands in addition to the ones needed by participants. * linkgit:git-am[1] to apply patches e-mailed in from your contributors. * linkgit:git-pull[1] to merge from your trusted lieutenants. * linkgit:git-format-patch[1] to prepare and send suggested alternative to contributors. * linkgit:git-revert[1] to undo botched commits. * linkgit: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]] ------------------------------------------------------ A repository administrator uses the following tools to set up and maintain access to the repository by developers. * linkgit:git-daemon[1] to allow anonymous download from repository. * linkgit: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. 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.