Git|Everyday GIT With 20 Commands Or So
Everyday GIT With 20 Commands Or So
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
Everybody uses these commands to maintain git repositories.
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git-init(1) or git-clone(1) to create a new repository.
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git-fsck(1) to check the repository for errors.
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git-gc(1) to do common housekeeping tasks such as repack and prune.
Examples
- Check health and remove cruft.
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$ git fsck (1) $ git count-objects (2) $ git gc (3)
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running without --full is usually cheap and assures the repository health reasonably well.
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check how many loose objects there are and how much disk space is wasted by not repacking.
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repacks the local repository and performs other housekeeping tasks.
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- Repack a small project into single pack.
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$ git gc (1)
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pack all the objects reachable from the refs into one pack, then remove the other packs.
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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.
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git-show-branch(1) to see where you are.
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git-log(1) to see what happened.
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git-checkout(1) and git-branch(1) to switch branches.
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git-add(1) to manage the index file.
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git-diff(1) and git-status(1) to see what you are in the middle of doing.
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git-commit(1) to advance the current branch.
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git-reset(1) and git-checkout(1) (with pathname parameters) to undo changes.
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git-merge(1) to merge between local branches.
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git-rebase(1) to maintain topic branches.
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git-tag(1) to mark known point.
Examples
- Use a tarball as a starting point for a new repository.
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$ 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)
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add everything under the current directory.
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make a lightweight, unannotated tag.
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- Create a topic branch and develop.
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$ 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)
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create a new topic branch.
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revert your botched changes in curses/ux_audio_oss.c.
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you need to tell git if you added a new file; removal and modification will be caught if you do git commit -a later.
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to see what changes you are committing.
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commit everything as you have tested, with your sign-off.
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take the last commit back, keeping what is in the working tree.
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look at the changes since the premature commit we took back.
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redo the commit undone in the previous step, using the message you originally wrote.
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switch to the master branch.
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merge a topic branch into your master branch.
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review commit logs; other forms to limit output can be combined and include --max-count=10 (show 10 commits), --until=2005-12-10, etc.
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view only the changes that touch what's in curses/ directory, since v2.43 tag.
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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.
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git-clone(1) from the upstream to prime your local repository.
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git-pull(1) and git-fetch(1) from "origin" to keep up-to-date with the upstream.
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git-push(1) to shared repository, if you adopt CVS style shared repository workflow.
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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.
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$ 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)
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repeat as needed.
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extract patches from your branch for e-mail submission.
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git pull fetches from origin by default and merges into the current branch.
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immediately after pulling, look at the changes done upstream since last time we checked, only in the area we are interested in.
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fetch from a specific branch from a specific repository and merge.
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revert the pull.
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garbage collect leftover objects from reverted pull.
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from time to time, obtain official tags from the origin and store them under .git/refs/tags/.
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- Push into another repository.
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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)
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mothership machine has a frotz repository under your home directory; clone from it to start a repository on the satellite machine.
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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.
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arrange git push to push local master branch to remotes/satellite/master branch of the mothership machine.
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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.
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on mothership machine, merge the work done on the satellite machine into the master branch.
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- Branch off of a specific tag.
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$ 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)
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create a private branch based on a well known (but somewhat behind) tag.
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forward port all changes in private2.6.14 branch to master branch without a formal "merging".
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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.
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git-am(1) to apply patches e-mailed in from your contributors.
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git-pull(1) to merge from your trusted lieutenants.
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git-format-patch(1) to prepare and send suggested alternative to contributors.
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git-revert(1) to undo botched commits.
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git-push(1) to publish the bleeding edge.
Examples
- My typical GIT day.
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$ 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)
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see what I was in the middle of doing, if any.
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see what topic branches I have and think about how ready they are.
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read mails, save ones that are applicable, and save others that are not quite ready.
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apply them, interactively, with my sign-offs.
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create topic branch as needed and apply, again with my sign-offs.
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rebase internal topic branch that has not been merged to the master, nor exposed as a part of a stable branch.
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restart pu every time from the next.
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and bundle topic branches still cooking.
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backport a critical fix.
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create a signed tag.
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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.
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push out the bleeding edge.
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push the tag out, too.
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Repository Administration
A repository administrator uses the following tools to set up and maintain access to the repository by developers.
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git-daemon(1) to allow anonymous download from repository.
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git-shell(1) can be used as a restricted login shell for shared central repository users.
update hook howto has a good example of managing a shared central repository.
Examples
- We assume the following in /etc/services
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$ grep 9418 /etc/services git 9418/tcp # Git Version Control System
- Run git-daemon to serve /pub/scm from inetd.
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$ 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.
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$ 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.
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$ 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
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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.
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in many distributions /etc/shells needs to list what is used as the login shell.
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- CVS-style shared repository.
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$ 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
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place the developers into the same git group.
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and make the shared repository writable by the group.
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use update-hook example by Carl from Documentation/howto/ for branch policy control.
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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.
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- HTTP server to support dumb protocol transfer.
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dev$ git update-server-info (1) dev$ ftp user@isp.example.com (2) ftp> cp -r .git /home/user/myproject.git
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make sure your info/refs and objects/info/packs are up-to-date
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upload to public HTTP server hosted by your ISP.
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