WIKI Liberasys

Cette page est en lecture seule. Vous pouvez afficher le texte source, mais ne pourrez pas le modifier. Contactez votre administrateur si vous pensez qu'il s'agit d'une erreur.
====== Git ======

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' | 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

==== 4) Push the commits to the remote repository ====

  # git push origin master

Then iterate to 3)