SYNOPSIS
Everyday Git With 20 Commands Or So
DESCRIPTION
Git users can broadly be grouped into four categories for the purposes of describing here a small set of useful commands for everyday Git.
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Individual Developer (Standalone) commands are essential for anybody who makes a commit, even for somebody who works alone.
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If you work with other people, you will need commands listed in the Individual Developer (Participant) section as well.
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People who play the Integrator role need to learn some more commands in addition to the above.
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Repository Administration commands are for system administrators who are responsible for the care and feeding of Git repositories.
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-init(1) to create a new repository.
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git-log(1) to see what happened.
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git-switch(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-restore(1) 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 a 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>-
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 switch -c alsa-audio <1> $ edit/compile/test $ git restore 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 diff HEAD^ <6> $ git commit -a --amend <7> $ git switch master <8> $ git merge alsa-audio <9> $ git log --since='3 days ago' <10> $ git log v2.43.. curses/ <11>-
create a new topic branch.
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revert your botched changes in
curses/ux_audio_oss.c. -
you need to tell Git if you added a new file; removal and modification will be caught if you do
git commit -alater. -
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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look at all your changes including the previous commit.
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amend the previous commit, adding all your new changes, using your original message.
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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
-10(to show up to 10 commits),--until=2005-12-10, etc. -
view only the changes that touch what’s in
curses/directory, sincev2.43tag.
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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.
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git-send-email(1) to send your e-mail submission without corruption by your MUA.
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git-request-pull(1) to create a summary of changes for your upstream to pull.
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 $ git switch -c mine master <1> $ edit/compile/test; git commit -a -s <2> $ git format-patch master <3> $ git send-email --to="person <email@example.com>" 00*.patch <4> $ git switch master <5> $ git pull <6> $ git log -p ORIG_HEAD.. arch/i386 include/asm-i386 <7> $ git ls-remote --heads http://git.kernel.org/.../jgarzik/libata-dev.git <8> $ git pull git://git.kernel.org/pub/.../jgarzik/libata-dev.git ALL <9> $ git reset --hard ORIG_HEAD <10> $ git gc <11>-
checkout a new branch
minefrom master. -
repeat as needed.
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extract patches from your branch, relative to master,
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and email them.
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return to
master, ready to see what’s new -
git pullfetches fromoriginby default and merges into the current branch. -
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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check the branch names in an external repository (if not known).
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fetch from a specific branch
ALLfrom a specific repository and merge it. -
revert the pull.
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garbage collect leftover objects from reverted pull.
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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 \ +refs/heads/*:refs/remotes/satellite/* <3> satellite$ edit/compile/test/commit satellite$ git push origin <4> mothership$ cd frotz mothership$ git switch master mothership$ git merge satellite/master <5>-
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 pullto fetch and store the branches of mothership machine to localremotes/origin/*remote-tracking branches. -
arrange
git pushto push all local branches to their corresponding branch of the mothership machine. -
push will stash all our work away on
remotes/satellite/*remote-tracking branches on the mothership machine. You could use this as a back-up method. Likewise, you can pretend that mothership "fetched" from you (useful when access is one sided). -
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 switch -c private2.6.14 v2.6.14 <1> $ edit/compile/test; git commit -a $ git checkout master $ git cherry-pick v2.6.14..private2.6.14 <2>-
create a private branch based on a well known (but somewhat behind) tag.
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forward port all changes in
private2.6.14branch tomasterbranch without a formal "merging". Or longhand
git format-patch -k -m --stdout v2.6.14..private2.6.14 | git am -3 -k
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An alternate participant submission mechanism is using the
git request-pull or pull-request mechanisms (e.g. as used on
GitHub (www.github.com) to notify your upstream of your
contribution.
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.
This section can also be used by those who respond to git
request-pull or pull-request on GitHub (www.github.com) to
integrate the work of others into their history. A sub-area
lieutenant for a repository will act both as a participant and
as an integrator.
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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
- A typical integrator’s Git day.
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$ git status <1> $ git branch --no-merged master <2> $ mailx <3> & s 2 3 4 5 ./+to-apply & s 7 8 ./+hold-linus & q $ git switch -c topic/one master $ git am -3 -i -s ./+to-apply <4> $ compile/test $ git switch -c hold/linus && git am -3 -i -s ./+hold-linus <5> $ git switch topic/one && git rebase master <6> $ git switch -C seen next <7> $ git merge topic/one topic/two && git merge hold/linus <8> $ git switch maint $ git cherry-pick master~4 <9> $ compile/test $ git tag -s -m "GIT 0.99.9x" v0.99.9x <10> $ git fetch ko && for branch in master maint next seen <11> do git show-branch ko/$branch $branch <12> done $ git push --follow-tags ko <13>-
see what you were in the middle of doing, if anything.
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see which branches haven’t been merged into
masteryet. Likewise for any other integration branches e.g.maint,nextandseen. -
read mails, save ones that are applicable, and save others that are not quite ready (other mail readers are available).
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apply them, interactively, with your sign-offs.
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create topic branch as needed and apply, again with sign-offs.
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rebase internal topic branch that has not been merged to the master or exposed as a part of a stable branch.
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restart
seenevery time from the next. -
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 master was not accidentally rewound beyond that already pushed out.
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In the output from
git show-branch,mastershould have everythingko/masterhas, andnextshould have everythingko/nexthas, etc. -
push out the bleeding edge, together with new tags that point into the pushed history.
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In this example, the ko shorthand points at the Git maintainer’s
repository at kernel.org, and looks like this:
(in .git/config)
[remote "ko"]
url = kernel.org:/pub/scm/git/git.git
fetch = refs/heads/*:refs/remotes/ko/*
push = refs/heads/master
push = refs/heads/next
push = +refs/heads/seen
push = refs/heads/maintRepository 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.
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git-http-backend(1) provides a server side implementation of Git-over-HTTP ("Smart http") allowing both fetch and push services.
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gitweb(1) provides a web front-end to Git repositories, which can be set-up using the git-instaweb(1) script.
update hook howto has a good example of managing a shared central repository.
In addition there are a number of other widely deployed hosting, browsing and reviewing solutions such as:
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gitolite, gerrit code review, cgit and others.
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/scmThe 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 using git-over-ssh.
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e.g. those using:
$ git push/pull ssh://host.xz/pub/scm/project$ 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-
log-in shell is set to /usr/bin/git-shell, which does not allow anything but
git pushandgit pull. The users require ssh access to the machine. -
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-
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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GIT
Part of the git(1) suite