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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.
* gitlink:git-init-db[1] or gitlink:git-clone[1] to create a
new repository.
* gitlink:git-fsck-objects[1] to check the repository for errors.
* gitlink:git-prune[1] to remove unused objects in the repository.
* gitlink:git-repack[1] to pack loose objects for efficiency.
Check health and remove cruft.::
$ git fsck-objects <1>
$ git prune
$ git count-objects <2>
$ git repack <3>
$ git prune <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> after repack, prune removes the duplicate loose objects.
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 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-checkout[1] and gitlink:git-branch[1] to switch
* gitlink:git-add[1] and gitlink:git-update-index[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-commit[1] to advance the current branch.
* 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-rebase[1] to maintain topic branches.
* gitlink:git-tag[1] to mark known point.
Use a tarball as a starting point for a new repository:
$ tar zxf frotz.tar.gz
$ cd frotz
$ git-init-db
$ 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 <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 pull . 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 "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'.
<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.
* gitlink:git-clone[1] from the upstream to prime your local
* 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
style shared repository workflow.
* gitlink:git-format-patch[1] to prepare e-mail submission, if
you adopt Linux kernel-style public forum workflow.
Clone the upstream and work on it. Feed changes to upstream.::
$ git clone git:// 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:// 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 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/.git frotz <1>
satellite$ cd frotz
satellite$ cat .git/remotes/origin <2>
URL: mothership:frotz/.git
Pull: master:origin
satellite$ echo 'Push: master:satellite' >>.git/remotes/origin <3>
satellite$ edit/compile/test/commit
satellite$ git push origin <4>
mothership$ cd frotz
mothership$ git checkout master
mothership$ git pull . satellite <5>
<1> mothership machine has a frotz repository under your home
directory; clone from it to start a repository on the satellite
<2> clone creates this file by default. It arranges "git pull"
to fetch and store the master branch head of mothership machine
to local "origin" branch.
<3> arrange "git push" to push local "master" branch to
"satellite" branch of the mothership machine.
<4> push will stash our work away on "satellite" 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)
<2> forward port all changes in private2.6.14 branch to master branch
without a formal "merging".
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.
* gitlink:git-am[1] to apply patches e-mailed in from your
* gitlink:git-pull[1] to merge from your trusted lieutenants.
* gitlink:git-format-patch[1] to prepare and send suggested
alternative to contributors.
* gitlink:git-revert[1] to undo botched commits.
* gitlink:git-push[1] to publish the bleeding edge.
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 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 master <7>
$ git pull . topic/one topic/two && git pull . 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
<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 master.
<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, and looks like this:
$ cat .git/remotes/ko
Pull: master:refs/tags/ko-master
Pull: maint:refs/tags/ko-maint
Push: master
Push: +pu
Push: maint
In the output from "git show-branch", "master" should have
everything "ko-master" 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.
* gitlink:git-daemon[1] to allow anonymous download from
* 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.
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
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>
$ grep git /etc/shells <2>
<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>
$ 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 <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.