Git
Install
sudo apt-get install git
Terminology
Git’s collaboration model is based on repository-to-repository interaction. In principle you push or pull commits from one repository to another.
- GitLab - web based interface to your Git repositories (GitHub)
- Staging Area - a place where we can group files together before we "commit" them to Git.
- Commit - is a snapshot of our repository. This way if we ever need to look back at the changes we've made (or if someone else does), we will see a nice timeline of all changes.
File status
- staged: Files are ready to be committed.
- unstaged: Files with changes that have not been prepared to be committed.
- untracked: Files aren't tracked by Git yet. This usually indicates a newly created file.
- deleted: File has been deleted and is waiting to be removed from Git.
- HEAD - is a pointer that holds your position within all your different commits. By default HEAD points to your most recent commit, so it can be used as a quick way to reference that commit without having to look up the SHA.
- Branching - are what naturally happens when you want to work on multiple features at the same time. You wouldn't want to end up with a master branch which has Feature A half done and Feature B half done. Rather you'd separate the code base into two "snapshots" (branches) and work on and commit to them separately. As soon as one was ready, you might merge this branch back into the master branch and push it to the remote server.
- Commands - are only relevant to directory that is tracked, it means it has .git/ tracking directory. Each time you use git commit changes are recorded in that directory.
Git settings - pre requisites
Specify your username and user email as these details are used each time you commit changes
git config --global user.email "piotr@example.com" git config --global user.name "Piotr" #name used for all your commits git config --global --list #list all of changes you made
Unset configuration
git config --global --unset http.proxy
Commands
Create new repository in a current directory
git init #creates hidden directory .git/ where changes are recorded all magic happens git status # show files status git log --summary #show details of each commit git diff #see changes, use HEAD argument for the current position in your commits
Create a new repository
git clone git@ourgit.example.com:piotr/ansible-training.git cd ansible-training touch README.md git add README.md git commit -m "add README" git push -u origin master
Existing folder or Git repository
cd existing_folder git init git remote add origin git@ourgit.example.com:piotr/ansible-training.git git add . git commit git push -u origin master
Move a repository from GitLab to other GitLab
Let's assume you did clone a repo to your local machine. Notice you created --bare repository (can only push/fetch can't commit)
git clone --bare git@old-github.com/yourLogin/repository.git
Then you create an empty repo in the new GitLab called yourRepoName, so you can upload/push to it
cd repository.git git remote remove origin #add new remote GitLab repository before push git remote add newgitlab git@new-github.com/yourLogin/yourRepoName.git git push --mirror newgitlab #push all branches and tags to new remote
This process also allows to change the project/repository name although you do not need to.
Create bare repository, central storage, GitLab repo
git init --bare project.git #this will create a folder called project.git (bare repository)
--bare flag creates a repository that doesn’t have a working directory, making it impossible to edit files and commit changes. Ultimately it creates the central repository for developers to push/commit their changes. GitLab new projects are created this way, become remote repository. Think of --bare as a way to mark a repository as a storage facility, opposed to a development environment.
Putting the Bare Repository on a Server
In preparation, you create a copy of project folder and place them in project.git pre-setup --bare folder
piotr@vmgitlab:~/git$ git clone --bare project project.git #project.git is ready to be moved to the server
Create a repository/project directory on the server. Need to be own by git:git user and group.
sudo -u git mkdir /var/opt/gitlab/git-data/repositories/your_gitlab_user
Assuming that /var/opt/gitlab/git-data/repositories/ (GitLab Omnibus) exists on that server, you can set up your new repository by copying your bare repository over:
local
user
scp -r project.git piotr@vmgitlab.home:project.git #copy repo to the server
sudo mv ~/project.git /var/opt/gitlab/git-data/repositories/piotrek #move to the right GitLab repo store path
Default remote repo path used by GitLab Omnibus installation
git:x:998:998::/var/opt/gitlab:/bin/sh git user home path GitLab repos store | / /var/opt/gitlab/git-data/repositories/piotrek | this is a namespace equals a username or group project name all projects .git folders are stored here
sudo chown -R git:git /var/opt/gitlab/git-data/repositories/piotrek/ #each file need to be owned by git:git
Add repo to GitLab, below command for Omnibus Installation. It will search, add and process all git repositories.
piotr@vmgitlab:~$ sudo gitlab-rake gitlab:import:repos
Processing piotrek/project.git
* Created gittest (piotrek/project.git) <- repo has been added
Processing piotrek/ansible.git
* ansible (piotrek/ansible.git) exists
Processing piotrek/ansible.wiki.git
* Skipping wiki repo
You will find the new project on the web interface of GitLab where it can be cloned from.
Add a file to a staging area for changes to be tracked
git add octocat.txt git add . #. means current directory and all subdirectories git add -A #add all files, even file deletions are included git add '*.txt' #add files using a wildcard, notice that quotes are required git reset <filename> #remove a file from staging area, the file and its changes will not be tracked
Committing (taking a snapshot of the repository)
The files are in the Staging Area, are not in a repository yet. To store our staged changes we run:
git commit -m "Description of what we changed"
Add local repository to remote GitHub server
creates repo on remote GitHub
name server and repository
git remote add origin https://vmgitlab.home/yourgitspace/gitrepo.git #uses https connection
git remote add origin git@vmgitlab.home:piotrek/ansible.git #SSH connection; this need to be created in first place via Gitlab, create/add new project
#Gitlab Omnibus server path for repos is /var/opt/gitlab/git-data/repositories/piotrek
#containing relevant directories: ansible.git and ansible.wiki.git
git remote -v #shows remote 'origin' repo path
origin git@vmgitlab.home:piotrek/ansible.git (fetch)
origin git@vmgitlab.home:piotrek/ansible.git (push)
Push to remote server
git push -u origin master #push commits to origin repo master branch, -u stores these parameters
Updating a local repo from a Remote Repository
Fetch changes from the remote repository
git fetch doesn’t touch a working tree at all but updates tracking system allowing you to decide what you want to do next
git fetch #download changes to local repo from remote 'origin/master' branch git diff master origin/master #compare local 'master' branch with remote 'origin/master' branch git merge origin/master #while working on 'master' (after a git checkout master) merge in the changes that you’ve just got from 'origin'
Pull changes and automagicly merge
git pull origin master #from the 'origin' remote repository its master branch git stash # to stash your not committed changes before pull git stash apply # to re-apply your changes after your pull
Preview changes of your staged files
git diff --staged
Working with branches
Revert a file version from the last commit
git checkout -- filename.txt git checkout $commit-id path/to/file
Create a new branch space to work for us
git branch branchname-newcode git branch -d branchname-newcode #deletes branch git branch -D branchname-newcode #forces delete since you cannot delete a branch that has not been merged, -D is equivalent -d -f
Change branch
git branch #list branches, one with asterisks it active current branch git checkout branchname-newcode #change to new branch
Remove files
git rm '*.txt' git rm -r folder_of_cats #remove folders recursively git commit -am "Delete stuff" #-a auto removes deleted files within commit
Merge other branch with the current active branch
git merge branchname-newcode
Git config - configuration
Git comes with a tool called git config that lets you get and set configuration variables that control all aspects of how Git looks and operates. These variables can be stored in three different places:
/etc/gitconfigcontains values for every user on the system and all their repositories. Option --system reads this file~/.gitconfigor~/.config/git/configspecific to your user, --global option writes to this file.git/configconfig file in the Git directory of whatever repository you’re currently using: option --local is specific to that single repository.
Each level overrides values in the previous level, so values in <.git/config trump those in /etc/gitconfig.
On Windows systems, Git looks for the .gitconfig file in the $HOME directory (C:\Users\$USER for most people). It also still looks for /etc/gitconfig, although it’s relative to the MSys root, which is wherever you decide to install Git on your Windows system when you run the installer. If you are using Git for Windows 2.x or later, there is also a system-level config file at C:\Documents and Settings\All Users\Application Data\Git\config on Windows XP, and in C:\ProgramData\Git\config on Windows Vista and newer. This config file can only be changed by git config -f <file> as an admin.
Add an empty directory to a repository
Although it's not supported by design to track an empty directories you can add .gitignore file
find . -name .git -prune -o -type d -empty -exec touch {}/.gitignore \;
with this content inside, however I've tested and an empty file did the job.
# Ignore everything in this directory * # Except this file !.gitignore
Remember to remove or alter the .gitignore file if you want to start tracking new files within such directory.