URL: https://linuxfr.org/users/ghusson/journaux/git-les-bases-et-guide-d-utilisation-en-mode-centralise-a-la-svn
Title: Git : les bases et guide d'utilisation en mode centralisé (à la SVN)
Authors: ghusson
Date: 2016年11月24日T10:17:12+01:00
License: CC By-SA
Tags: svn, repository, centralisé, liberasys et git
Score: -2
Après une demi journée passée à lire de la documentation sur git, je partage la synthèse.
Mon besoin est de créer un repository central et de travailler à la manière de SVN.
Remarque : GIT est à la base conçu pour travailler de manière décentralisée.
Pour ma société Liberasys, je voulais quelque chose de simple, efficace. Le mode de fonctionnement SVN correspond à ce que je veux.
Les notes sont en anglais, désolé pour les non anglophones.
```bash
# from : https://git-scm.com/docs/gitcore-tutorial
# Directories
.git/objects/ : real repository data (identified by SHA-1)
.git/refs/ : references to objects (heads of development, revision tags)
# Remarquable files
.git/HEAD : Master head : points to default branch
.git/index : describes your current working tree
# Objects types and content
# RQ : objects are immutable
git cat-file -t 557db03de997c86a4a028e1ebd3a1ceb225be238 : gives the type of the file
git cat-file blob 557db03de997c86a4a028e1ebd3a1ceb225be238 : gives the content of the file
# Diff commands and comparisons (by Jon Loeliger) :
 diff-tree
 +----+
 | |
 | |
 V V
 +-----------+
 | Object DB |
 | Backing |
 | Store |
 +-----------+
 ^ ^
 | |
 | | diff-index --cached
 | |
diff-index | V
 | +-----------+
 | | Index |
 | | "cache" |
 | +-----------+
 | ^
 | |
 | | diff-files
 | |
 V V
 +-----------+
 | Working |
 | Directory |
 +-----------+
# Configure information about git user
git config --global user.email "user@domain"
git config --global user.name "firstname lastname"
# Initialise git repository
mkdir test && cd test
git init
# Populating repository
echo "Hello World">hello
# Index (cache)
echo "Silly example">example
git update-index --add hello example
# Get diff-files : difference between current working directory and index file
git diff-files : raw summary
git diff : readable differences (= git diff-files -p)
# Get diff-index
git diff HEAD (= git diff-index -p HEAD) : differences between a commited tree and the working directory
git diff-index --cached -p HEAD : compares a tree and the index cache content
# Create a tree
git write-tree : Raw way to create a tree
# Create initial master tree (new commited tree, related to nothing else : the master tree)
tree=$(git write-tree)
commit=$(echo 'Initial commit' | git commit-tree $tree)
git update-ref HEAD $commit
# Making a change
# Process : working tree -> index file -> commited tree
git rm <file> : remove files from index (=git update-index --remove <file>)
git add <file : add files to index (= git update-index --add <file>)
git update-index hello example : updates index of files
git diff : show differences with index
git diff HEAD : show the differences with a tree (HEAD pointer tree)
git commit : store a change in the repository, give a commit message !
 : all lines beginning with # will be ignored
 
# Get diff-tree : difference between two trees
git diff-tree -p HEAD : difference between the commited tree and the master tree
git diff-tree -p HEAD --pretty : idem, with metadata of commits
# Tags
git tag my-first-tag : light tag (branch put in the .git/refs/tags/ diretory rather than .git/logs/refs/heads)
git diff my-first-tag : diff between the tag and the working directory
git tag -s my-major-tag : real git object, will sign current HEAD
git tag <tagname> <mybranch> : tag from a branch
# Branches
git checkout -b <mybranch> : creates a branch (pointer into the Git object database in .git/refs/heads/)
git checkout -b <mybranch> <earlier-commit> : creates a branch from an earlyer commit (tag or branch)
git branch : displays the current branch
# Copy locally a repository
cp -a repo-src repo-dst
cd repo-dst
git reset # does :
 git read-tree --reset HEAD # total index rebuild
 git update-index --refresh # makes sure to match up all index entries with the checked-out files
# Copy remotely a repository
git clone git://git.kernel.org/pub/scm/git/git.git/ my-git
cd my-git
git checkout
# Switch between tags and branches
git checkout <name> : name can be a branch or a tag
# === Git, SVN way (with user groups) / server
# install git-core and git packages
adduser git
mkdir /pub
mkdir /pub/my-repo.git
chown -R git:git /pub/my-repo.git
su - git
cd /pub/my-repo.git
git --bare init --shared
# gives SSH accces to this directory from the users
# remark : you can use git-shell in order to limit system exposure
# as root:
USERNAME="myuser"
KEYSDIR="/data/keys"
adduser --shell /usr/bin/git-shell --ingroup git --disabled-password ${USERNAME}
mkdir -p ${KEYSDIR}/${USERNAME}
cd ${KEYSDIR}/${USERNAME}
ssh-keygen -t rsa -b 4096 -f ${USERNAME}_rsa_4096 -P ""
mkdir /home/${USERNAME}/.ssh
cp ${USERNAME}_rsa_4096.pub /home/${USERNAME}/.ssh/authorized_keys
chmod 700 /home/${USERNAME}/.ssh
chmod 600 /home/${USERNAME}/.ssh/authorized_keys
chown -R ${USERNAME}:git /home/${USERNAME}/.ssh
# now send the ${USERNAME}_rsa_4096 file to your new user
# ask him to put a passphrase to the key with :
ssh-keygen -f <keyfile> -p
# ask him to put the file in ~/.ssh/git_<original key file name>
# === Git, SVN way (with user groups) / user
# if not already done for the user :
git config --global user.email "user@domain"
git config --global user.name "firstname lastname"
# 1) === initial clone
export GIT_SSH_COMMAND='ssh -i <private_key_file>'
git clone foo.com:/pub/my-repo.git
cd my-repo
# remark : either do the export each time you use a new shell, either configure the .ssh/config file
# 2) TO DO ONLY ONE TIME : create master tree and HEAD link
tree=$(git write-tree)
commit=$(echo 'Initial commit' &#124; git commit-tree $tree)
git update-ref HEAD $commit
git push origin master
# 3) === make local changes then commit them locally
# do not forget git add/rm/mv
git diff
git diff -p HEAD
git commit
# or :
git commit -a
# 4) === fetch changes from remote repository (merge them with local repository - always commit before)
git pull origin
# 5) === push the commits to the remote repository
git push origin master
# then iterate to 3)
```
Je ne sais pas si le mode de fonctionnement proposé est "carré". Je compte sur les commentaires acerbes des lecteurs :-)
En tout cas cela fonctionne avec mes tests initiaux. J'espère que cela motivera certains à essayer voir à utiliser git au quotidien ?
Par ailleurs, quand je voudrai libérer des sources, je me demande si un téléversement d'un repository sera possible et aisé vers github ou gitlab (avec reprise des versions et métadonnées) ?
PS : la clef SSH initiale générée pour un utilisateur est non chiffrée. il faut donc la transmettre de manière sécurisée.
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="httpS://linuxfr.org/users/ghusson/journaux/git-les-bases-et-guide-d-utilisation-en-mode-centralise-a-la-svn.md">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="httpS://linuxfr.org/users/ghusson/journaux/git-les-bases-et-guide-d-utilisation-en-mode-centralise-a-la-svn.md" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>