Git is a software that allows you to keep track of changes made to a project over time. Git works by recording the changes you make to a project, storing those changes, then allowing you to reference them as needed.
- github-notes
- A Working Directory: where you'll be doing all the work: creating, editing, deleting and organizing files
- A Staging Area: where you'll list changes you make to the working directory
- "Tracked files"
- A Repository: where Git permanently stores those changes as different versions of the project
- Changes are saved as a commit
git init
- Initializes an empty Git repository in the current working directory.
- Sets up the tools Git needs to begin tracking changes on the current project.
- Creates a hidden folder /.git/ in the directory where git operates.
git status
- Lists any changes of the contents in the working directory.
- Untracked files will be displayed in red
- Untracked files do not have any changes stored.
- Green files show changes to a file that need to be committed.
git add <file>
- Adds the specified file to the staging area.
- Specified file is now tracked if it was untracked.
git remote add <remote name> <URL>
git remote add origin https://github.com/user/repo.git- is the destination of a remote repository.
- The name is anything you give it.
- This adds your local repo to the remote one.
git add .
- Shortcut method that will add all files in the current directory except for the ignored files.
- Ignored files are stored within .gitignore/
- You can check the differences between tracked local files and files in the repo or staging area.
git diff <file>
- Displays changes to a tracked file between the local file and those added to the staging area
- Additions to the file are preceded by a + and in green
- Any missing lines are preceded by a – and in red
- The same lines are in white
git diff HEAD
- The most recent change to the last file you committed.
git diff {branch}@{1} {branch}
- Displays differences between previous branch version and current version.
- The previous version is one which was last pushed to repo.
git status
- Lists the current branch and any differences
- When it says 'up-to-date' it means up-to-date with the branch that the current branch tracks.
- Usually this is the local reference
- Not "up-to-date with the latest live status of the upstream.
git checkout -b <branch-name>
- Create a new branch locally.
git commit -a
- Automatically stage every file that is already tracked.
- Skips
git addstep.
- Skips
git push -u <origin> <branch-name>
- To push a local new branch to the remote
- -u stands for –set-upstream
- tells git to remember all of the commands so that will execute the same command as an alias now.
git pull <origin> <branchName>
- Returns any changes that have been made to the files under the folder name.
- Brings the local branch up-to-date with the remote branch.
- Combines
git fetchandgit merge
git commit
- Any files added to the unstaged area which have been changed can be committed to the repository.
git fetch
- A local repo won't reflect changes that have been made on the remote repo, so it must be updated first before changes are made.
fetchgets up to date with the commits from the remote repo- This does not update the local files so it will not change your local working copy.
git merge
- merge moves those commits to the local branch
git rm <file>
- Removes the file from the working directory and from tracked files.
- If you remove the file from the working directory
- For all locally staged files
git reset --hard - For a single file
git checkout <filename>
git log
- Lists commits made in a repository in reverse chronological order.
- Commit history includes:
- SHA-1 checksum
- Author's name and email
- Date written
- Commit message
-p
- Shows difference introduced from each commit.
- If following the
-pflag by a number, then it will limit the output to the max number of commits.
--since=<n>.weeks
- Shows commits occuring within the last n weeks.
--S<string>
-
Displays commits that changed the specified string.
git log --Sfunction_name- Displays all commits where the function_name was added or removed.
--author
- Displays commits by a specified author.
git commit -amend
- If a commit message is messed up or files were forgotten to be restaged, you can redo the commit message.
git branch
- Lists all branches of repository
- Current branch is preceded by an asterisk
git fetch
- Run git fetch first to make sure the local branch is updated.
git branch
- List all available branches
git diff (local-branch) (remote-branch)
- Compare the differences between each branch.
- The first listed branch is considered branch A and the second branch is branch B
- Any changes that are within A that are not in B are preceded by a – and listed in red.
- Any changes within B but not in A are preceded with a + and listed in green.
- Initialize the local directory as a git directory
git init - Add all files currently in the directory to be staged for commit
git add . - Commit the files you've staged
git commit -m "First commit" - Create the new repository on github
- Get the github repository's URL from the quick setup page
- Add the url for the remote repository
git remote add origin <URL>git remote -v - Push the changes to master branch
git push origin master
- Git provides https or SSH to download and upload.
-
The command
ssh-keygenwill generate a private and public OpenSSH key with the default nameid_rsa- The key will be located at
~/.ssh/~/.sshis shorthand for the current user's home directory.- The location of the ssh key will be stored in
/home/<username>/.ssh/
- The key will be located at
-
Github email address is address you use to login
ssh-keygen -t rsa -b 4096 -C “[email protected]”-tspecifies the type of key.-bspecifies the number of bits in the key to create.- default is 2048 bits
-Cadds a comment- The comment is only serving as a label and not functionality. It can be generated without it, such as an SSH key for a shared repo on a shared server.
-
An SSH key will be generated in a file.
-
May add a passphrase for added security.
-
ssh-agent manages your SSH keys.
- the key must be added to ssh-agent to use
-
Generate an agent id:
eval $(ssh-agent -s) -
Add the private key to the ssh-agent
ssh-add ~/.ssh/<private_key_name>
-
Adding an SSH key to your account will allow you to push/pull to all of your GitHub repos from the server where the SSH key exists since it is identifying the server as you.
- If this server will be accessible by others, consider using a deploy key for a specific repo.
-
Check for existing keys
ls -al ~/.ssh- will have a .pub extension for the public key
- The private key will be the same name without an extension.
-
Copy the SSH key to your clipboard
clip < ~/.ssh/id_rsa.pub- This will only work if you are working on a local terminal. If you are using PuTTY or another SSH client, then use copying SSH remotely
-
Go to your user settings on github.
-
Click on SSH and GPG keys.
-
The “Title” field is only descriptive.
- Name it after the computer that is accessing github
-
“Key” field
- Paste in the SSH key that was generated through ssh-keygen
- If using PuTTY or any other remote SSH client, print the key to the shell:
ssh-keygen -y -f <key location>
-youtputs the public key-finput file<key location>- Usually located at ~/.ssh/id_rsa
- Log into root user
sudo su - Run
ssh-keygento generate a key.- If a key already exists you can check with
ls -al ~/.ssh - Leave blank for name and passphrase. The name will default to id_rsa.
- If wanting to use an SSH agent:
- Generate an agent id:
eval $(ssh-agent -s) - Add the private key to the ssh-agent
ssh-add ~/.ssh/<private_key_name>
- Generate an agent id:
- If a key already exists you can check with
- Print the
ssh-keygen -y -f ~/.ssh/id_rsaand copy.- If you highlight the text with RMB in PuTTY it will automatically copy.
- Paste this key into the repo's deploy keys.
- Test connection to github
ssh -T [email protected]- If successful what should be displayed is
Hi {username/repo} You\'ve successfully authenticated, but GitHub does not provide shell access. - Try interacting with the repo!
- clone
- push
- pull
To clone a repository from GitHub onto your local machine:
- After code has been completed in your local environment, commit to the GitHub repo by adding a message and pushing to the repo.
- This can also be done through a CLI with:
git add <file>
git commit -m "<message>"
git push
- GitHub desktop downloads and updates to the folder you specified when cloning.
- If there are multiple branches, the folder only contains contents of the current branch.
- Contents of branches do not simultaneously exist in the same folder.
- You must switch to a different branch through GitHub desktop or the CLI to load those branches.
- If there are multiple branches, the folder only contains contents of the current branch.
- GitHub Desktop can open files to be edited in your favorite IDE:
- Fires off custom scripts when events occur in the repo.
- Can reside in either local or server-side repositories.
- Hooks are stored in the .git/hooks/ folder of a repo
- The scripts in the /hooks/ folder must be executable and first line must be a shebang magic number that calls the correct script interpreter.
- All default hooks have the extension
.sample- Must remove
.samplefor the script to execute
- Must remove
- Triggered by committing or merging
- Receive pushed commits
- Scripts run before and after pushes to the server.
- When there is a push from a client:
pre-receive- Makes sure none of the updated references are non-fast-forwards.
- If pusher is trying to push to multiple branches, runs only once.
update- Run once for each branch the pusher is trying to update.
- If pusher trying to push to multiple branches, runs once per branch they're pushing to.
post-receive- Can be used to update other services or notify users.
- notifying a CI server
- update ticket-tracking system
- Can be used to update other services or notify users.
- Stored in hooks subdirectory of Git project.
- Usually
.git/hooks
- Usually
git push -u <origin> <branch>
ssh: Could not resolve hostname https: Name or service not known.- The hostname stored in origin is most likely wrong.
- Double check it with:
git remote -vcompared to the link provided at the GitHub repo. - To change the url:
git remote set-url <origin> <URL>
-
The hostname stored in origin is most likely wrong.
-
Double check it with:
git remote -vcompared to the link provided at the GitHub repo. -
To change the url:
git remote set-url <origin> <URL> -
If the remote url is correct and you are using the HTTPS method, then try storing credentials with git:
$ git config credential.helper store
$ git push http://example.com/repo.git
Username: <type your username>
Password: <type your password>git config credential.https://example.com.username myusername
git help credentialsprovides the manual page for how git stores credientials.
git push -u <origin> <branch>
remote: Repository not foundgit checkout
you are on a branch yet to be born- Make sure the repository has been initialized locally
- Make sure the repository exists on github.
- Make sure the local repository knows of the remote repository.
- Double check it with:
git remote -v- If it does not know of the remote repository, get the repository’s address from github.
- Double check it with:
git remote add <origin-name> <url>
- Add the contents of the folder to be staged:
git add . - Commit the file:
git commit -m “commit message” - Double check you are on the same branch you are trying to push to
git status - If you are not, check the local branches:
git branch - If it does not exist locally
git checkout -b <branch-name> - Push the file
git push -u <origin-name> <branch-name>
Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.- Run
ssh -vT [email protected] - Start ssh-agent
ssh-agent -s - Check that a public key is loaded into ssh-agent
ssh-add -l
git fetch -all
git reset --hard origin/<branch_name>