Download and installation
-------------------------
-Unix users: download and install using your package manager.
+Unix users: `download and install using your package manager
+<https://git-scm.com/download/linux>`_.
Microsoft Windows: download `git-for-windows
<https://github.com/git-for-windows/git/releases>`_ or `msysGit
Examples of git commands in this PEP use the following approach. It is
supposed that you, the user, works with a local repository named
``python`` that has an upstream remote repo named ``origin``. Your
-local repo has two branches ``v1`` and ``v2``. For most examples the
-currently checked out branch is ``v2``. That is, it's assumed you have
-done something like that::
+local repo has two branches ``v1`` and ``master``. For most examples
+the currently checked out branch is ``master``. That is, it's assumed
+you have done something like that::
- $ git clone -b v2 http://git.python.org/python.git
+ $ git clone http://git.python.org/python.git
$ cd python
$ git branch v1 origin/v1
The first command clones remote repository into local directory
-`python``, creates a new local branch v2, sets remotes/origin/v2 as
-its upstream remote-tracking branch and checks it out into the working
-directory.
+`python``, creates a new local branch master, sets
+remotes/origin/master as its upstream remote-tracking branch and
+checks it out into the working directory.
The last command creates a new local branch v1 and sets
remotes/origin/v1 as its upstream remote-tracking branch.
$ git clone -b v1 http://git.python.org/python.git
$ cd python
- $ git checkout --track origin/v2
+ $ git checkout --track origin/master
-The last command creates a new local branch v2, sets remotes/origin/v2
-as its upstream remote-tracking branch and checks it out into the
-working directory.
+The last command creates a new local branch master, sets
+remotes/origin/master as its upstream remote-tracking branch and
+checks it out into the working directory.
Branches and branches
local repository. They are there for you to remember what branches and
commits have been pulled from and pushed to what remote repos (you can
pull from and push to many remotes). Remote-tracking branches live
-under ``remotes/$REMOTE`` namespaces, e.g. ``remotes/origin/v2``.
+under ``remotes/$REMOTE`` namespaces, e.g. ``remotes/origin/master``.
To see the status of remote-tracking branches run::
$ git fetch $REMOTE $BRANCH:$BRANCH
The first command fetches commits from the named $BRANCH in the
-$REMOTE repository that are not in your repository and leaves the id
-(the hash) of the head commit in file .git/FETCH_HEAD and updates
-remote-tracking branch.
+$REMOTE repository that are not in your repository, updates
+remote-tracking branch and leaves the id (the hash) of the head commit
+in file .git/FETCH_HEAD.
The second command fetches commits from the named $BRANCH in the
$REMOTE repository that are not in your repository and updates both
that non-current branch and then merge::
$ git fetch origin v1:v1 # Update v1
- $ git pull --rebase origin v2 # Update the current branch v2 using
- # rebase instead of merge
+ $ git pull --rebase origin master # Update the current branch master
+ # using rebase instead of merge
$ git merge v1
If you have not yet pushed commits on ``v1``, though, the scenario has
$ git checkout v1
$ git pull --rebase origin v1
- $ git checkout v2
- $ git pull --rebase origin v2
+ $ git checkout master
+ $ git pull --rebase origin master
$ git merge v1
It is possible to configure git to make it fetch/pull a few branches
::
- $ git push origin v1 v2
+ $ git push origin v1 master
-git pushes local v1 to remote v1 and local v2 to remote v2. The same
-as::
+git pushes local v1 to remote v1 and local master to remote master.
+The same as::
- $ git push origin v1:v1 v2:v2
+ $ git push origin v1:v1 master:master
Git pushes commits to the remote repo and updates remote-tracking
branches. Git refuses to push commits that aren't fast-forwardable.
from the workstation to a bare repo on the remote host, ssh to the
remote host and pull from the bare repo to a non-bare deployment repo.
+That changed in git 2.3, but see `the blog post
+<https://github.com/blog/1957-git-2-3-has-been-released#push-to-deploy>`_
+for caveats; in 2.4 the push-to-deploy feature was `further improved
+<https://github.com/blog/1994-git-2-4-atomic-pushes-push-to-deploy-and-more#push-to-deploy-improvements>`_.
+
Tags
''''
For example::
- $ git fetch origin tag 1.4.2 tag 2.1.7
+ $ git fetch origin tag 1.4.2
+ $ git fetch origin v1:v1 tag 2.1.7
Git doesn't automatically pushes tags. That allows you to have private
-tags (lightweight tags are also private for a repo, they cannot be
-pushed). To push tags list them explicitly::
+tags. To push tags list them explicitly::
$ git push origin tag 1.4.2
- $ git push origin v1 v2 tag 2.1.7
+ $ git push origin v1 master tag 2.1.7
Don't move tags with ``git tag -f`` or remove tags with ``git tag -d``
after they have been published.
+Private information
+'''''''''''''''''''
+
+When cloning/fetching/pulling/pushing git copies only database objects
+(commits, trees, files and tags) and symbolic references (branches and
+lightweight tags). Everything else is private to the repository and
+never cloned, updated or pushed. It's your config, your hooks, your
+private exclude file.
+
+If you want to distribute hooks, copy them to the working tree, add,
+commit, push and instruct the team to update ind install the hook
+manually.
+
Commit editing and caveats
==========================
To see what commits have not been published yet compare the head of the
branch with its upstream remote-tracking branch::
- $ git log origin/v2..
+ $ git log origin/master..
$ git log origin/v1..v1
For every branch that has an upstream remote-tracking branch git
It is in ``git help rebase``.
On the other hand don't be too afraid about commit editing. You can
-safely edit, remove, reorder, combine and split commits that hasn't
+safely edit, remove, reorder, combine and split commits that haven't
been pushed yet. You can even push commits to your own (backup) repo,
-edit them later and force-push edited commits to replace what has
+edit them later and force-push edited commits to replace what have
already been pushed. Not a problem until commits are in a public
or shared repository.
In a more complex situation you'd want to move some commits along with
resetting the head of the branch. Cherry-pick them to the new branch.
-For example, if you want to reset the branch ``v2`` back to the
+For example, if you want to reset the branch ``master`` back to the
original commit but preserve two commits created in the current branch
do something like::
- $ git branch save-v2 # create a new branch saving v2
- $ git reflog # find the original place of v2
+ $ git branch save-master # create a new branch saving master
+ $ git reflog # find the original place of master
$ git reset $COMMIT_ID
- $ git cherry-pick save-v2~ save-v2
- $ git branch -D save-v2 # remove temporary branch
+ $ git cherry-pick save-master~ save-master
+ $ git branch -D save-master # remove temporary branch
git revert: revert a commit
---------------------------
``git revert`` reverts a commit or commits, that is, it creates a new
-commit or commits that reverts the effects of the given commits. It's
-the only way to undo published commits (``git commit --amend``, ``git
-rebase`` and ``git reset`` change the branch in non-fast-forwardable
-ways so they should only be used for non-pushed commits.)
+commit or commits that revert(s) the effects of the given commits.
+It's the only way to undo published commits (``git commit --amend``,
+``git rebase`` and ``git reset`` change the branch in
+non-fast-forwardable ways so they should only be used for non-pushed
+commits.)
There is a problem with reverting a merge commit. ``git revert`` can
undo the code created by the merge commit but it cannot undo the fact
For example::
$ git config branch.v1.rebase true
- $ git config branch.v2.rebase true
+ $ git config branch.master.rebase true
-After that ``git pull origin v2`` becomes equivalent to ``git pull
---rebase origin v2``.
+After that ``git pull origin master`` becomes equivalent to ``git pull
+--rebase origin master``.
In case when merge is preferred it is recommended to create new
commits in a separate feature or topic branch while using rebase to
$ git checkout -b issue-42 # create a new issue branch and switch to it
...edit/test/commit...
- $ git checkout v2
- $ git pull --rebase origin v2 # update v2 from the upstream
+ $ git checkout master
+ $ git pull --rebase origin master # update master from the upstream
$ git merge issue-42
$ git branch -d issue-42 # delete the topic branch
- $ git push origin v2
+ $ git push origin master
When the topic branch is deleted only the label is removed, commits
-are stayed in the database, they are now merged into v2::
+are stayed in the database, they are now merged into master::
- o--o--o--o--o--M--< v2 - the mainline branch
+ o--o--o--o--o--M--< master - the mainline branch
\ /
- --*--*--* - the topic branch, now unnamed
+ --*--*--* - the topic branch, now unnamed
The topic branch is deleted to avoid cluttering branch namespace with
small topic branches. Information on what issue was fixed or what
Git has a builtin merge strategy for what Python core developers call
"null-merge"::
- $ git merge -s ours v1 # null-merge v1 into v2
+ $ git merge -s ours v1 # null-merge v1 into master
-ReReRe
-======
+Advanced configuration
+======================
-https://git-scm.com/book/en/Git-Tools-Rerere
+Line endings
+------------
+
+Git has builtin mechanisms to handle line endings between platforms
+with different EOL styles. To allow git to do CRLF conversion assign
+``text`` attribute to files using `.gitattributes
+<https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html>`_.
+For files that have to have specific line ending assign ``eol``
+attribute. For binary files the attribute is, naturally, ``binary``.
+
+For example::
+
+ $ cat .gitattributes
+ *.py text
+ *.txt text
+ *.png binary
+ /readme.txt eol=CRLF
+
+To check what attributes git uses for files use ``git check-attr``
+command. For example::
+
+$ git check-attr -a -- \*.py
Advanced topics
Staging area
------------
-Staging area aka index is a distinguishing feature of git. See
-`WhatIsTheIndex
+Staging area aka index aka cache is a distinguishing feature of git.
+Staging area is where git collects patches before committing them.
+Separation between collecting patches and commit phases provides a
+very useful feature of git: one can review collected patches before
+commit and even edit them - remove some hunks, add new hunks and
+review again.
+
+To add files to the index use ``git add``. Collecting patches before
+committing means you need to do that for every change, not only to add
+new (untracked) files. To simplify committing in case you just want to
+commit everything without reviewing run ``git commit --all`` (or just
+``-a``) - the command adds every changed tracked file to the index and
+then commit. To commit a file or files regardless of patches collected
+in the index run ``git commit [--only|-o] -- $FILE...``.
+
+To add hunks of patches to the index use ``git add --patch`` (or just
+``-p``). To remove collected files from the index use ``git reset HEAD
+-- $FILE...`` To add/inspect/remove collected hunks use ``git add
+--interactive`` (``-i``).
+
+To see the diff between the index and the last commit (i.e., collected
+patches) use ``git diff --cached``. To see the diff between the
+working tree and the index (i.e., uncollected patches) use just ``git
+diff``. To see the diff between the working tree and the last commit
+(i.e., both collected and uncollected patches) run ``git diff HEAD``.
+
+See `WhatIsTheIndex
<https://git.wiki.kernel.org/index.php/WhatIsTheIndex>`_ and
`IndexCommandQuickref
<https://git.wiki.kernel.org/index.php/IndexCommandQuickref>`_ in Git
Wiki.
-Advanced configuration
-======================
-
-Line endings
-------------
-
-Git has builtin mechanisms to handle line endings.
+ReReRe
+======
-TODO: describe crlf configuration and .gitattributes.
+https://git-scm.com/book/en/Git-Tools-Rerere
Database maintenance
====================
-TODO: dangling objects, git gc, git repack.
-
-https://gcc.gnu.org/ml/gcc/2007-12/msg00165.html
-
-http://vcscompare.blogspot.ru/2008/06/git-repack-parameters.html
+Git object database and other files/directories under ``.git`` require
+periodic maintenance and cleanup. For example, commit editing left
+unreferenced objects (dangling objects, in git terminology) and these
+objects should be pruned to avoid collecting cruft in the DB. The
+command ``git gc`` is used for maintenance. Git automatically runs
+``git gc --auto`` as a part of some commands to do quick maintenance.
+Users are recommended to run ``git gc --aggressive`` from time to
+time; ``git help gc`` recommends to run it every few hundred
+changesets; for more intensive projects it should be something like
+once a week and less frequently (biweekly or monthly) for lesser
+active projects.
+
+``git gc --aggressive`` not only removes dangling objects, it also
+repacks object database into indexed and better optimized pack(s); it
+also packs symbolic references (branches and tags). Another way to do
+it is to run ``git repack``.
+
+There is a well-known `message
+<https://gcc.gnu.org/ml/gcc/2007-12/msg00165.html>`_ from Linus
+Torvalds regarding "stupidity" of ``git gc --aggressive``. The message
+can safely be ignored now. It is old and outdated, ``git gc
+--aggressive`` became much better since that time.
+
+For those who still prefer ``git repack`` over ``git gc --aggressive``
+the recommended parameters are ``git repack -a -d -f --depth=20
+--window=250``. See `this detailed experiment
+<http://vcscompare.blogspot.ru/2008/06/git-repack-parameters.html>`_
+for explanation on the effects of these parameters.
+
+From time to time run ``git fsck [--strict]`` to verify integrity of
+the database. ``git fsck`` could report dangling objects; that's not
+an error, just a reminder to perform regular maintenance.
Tips and tricks
git on server
=============
-TODO: anonymous access; git over ssh; gitolite; gitweb; cgit; gitlab.
+TODO: anonymous access (``git daemon``); git over ssh; gitolite;
+gitweb; cgit; Kallithea; pagure; gogs and gitea; gitlab.
http://gitolite.com/gitolite/index.html
http://git.zx2c4.com/cgit/
+https://kallithea-scm.org/
+
+https://pagure.io/
+
+http://gogs.io/ and http://gitea.io/
+
+https://about.gitlab.com/
+
+
From Mercurial to git
=====================
projects / git-wiki.git / blobdiff