Ashis Kumer Biswas

Ashis Kumer Biswas

Assistant Professor

Github commands at the command line: a typical workflow with github

6 minute read

Make sure to authenticate your github pass token at the command line. You may find my this blog post useful: Github command line with new authentication.

Frequently used git commands

Command Purpose
git clone https://github.com/xxx/my-repo.git clone repo
git pull fetch and merge any commits from the tracking remote branch.
git status track changes
git add a_file.txt adds a_file.txt into staging area
git add --all adds everything in the dir into staging area
git commit -m "a message" commits everything at the current staging area
git push pushes latest commit into the remote repo
git push origin branchX pushes latest commit into the remote repo branch named branchX

List of git commands

Command Purpose
git clone https://github.com/xxx/my-repo.git clone repo
git pull fetch and merge any commits from the tracking remote branch.
git status track changes
git diff shows file differences not yet staged
git diff --staged shows file differences between staging and the last file version
git branch Lists all local branches in the current repository
git branch branchZ Creates a new branch named branchZ
git log -3 check the last 3 logs of git repository
git log --graph draw text-based graphical representation of commit history
git add a_file.txt adds a_file.txt into staging area
git add --all adds everything in the dir into staging area
git commit -m "a message" commits everything at the current staging area
git config --global user.email "[email protected]" a configuration required to post commits
git config --global user.name "myname" another configuration required to post any commmit
git push pushes latest commit into the remote repo
git push origin branchX pushes latest commit into the remote repo branch named branchX
git checkout -- another_file.txt undoing file modifications before staging (with git add) is performed
git reset HEAD a_file.txt unstaging any staged changes on a_file.txt, but preserving its contents.
git reset HEAD~ undoing latest commit
git checkout -b branchY create a new branch, and automatically land on the new branch named branchY
git checkout branchX switch to branch branchX
git checkout master; git merge branchX this is how to merge branchX branch to the master branch.
git branch -d branchY delete a branch named branchY

Clone a repository

  • In your local computer, change current working directory to the directory where you want to clone a github repository. Say, cd _myGITs/
  • git clone https://github.com/xxx/my-repo.git
    • The git clone command copies your repository from the Github into your local directory.
  • cd my-repo
    • And, inspect ls -a, and you will find .git, .gitignore files besides the repository contents.

Make changes to your repository

  • Anything you’d like with editors you have in your local system. You can add/edit/remove files as you go.

Track and add changes to the local git repo

  • git status
    • This will display a list of modifications made.
  • git add README.md a_file.txt
  • This will add one or more files which are listed changes into the staging area
  • You may use git add --all, but it is strongly discouraged as you may accidentally add things like credential files. If you really want to do it regardless, move sensitive data out of the repository.
  • git commit -m "a message meaningful enough for the people you work with
    • It takes everything from the staging area and makes a permanent snapshot of the current state of the repository that is associated with a unique id.
    • First attemt of git commit command may ask you to set the user.email and user.name values:
      • git config --global user.email "[email protected]"
      • git config --global user.email "my name is xxx"

Push changes to Github (i.e., push to remote)

  • So far we have only modified our local (revised) copy of the repository we were working in.
  • To add the changes to your remote git repo, you need to git push them to Github.
  • You can push your changes to Github with git push
    • You will then be prompted for Github authentication (if not set already with gh auth login, or the stored access token not having correct privileges to make those changes).

Undoing unstaged changes (i.e., prior to calling git add)

  • If a file has been changed, but the changes have not yet been staged with git add, then the changes can be undone using git checkout -- myFile.txt
    • This will discard the changes made on the myFile.txt. The command git checkout -- will revert back to the last committed version.
    • Check the status with git status to see if the undoing was successful.

Undoing staged changes (i.e., after changes are added with git add)

  • Once you add a set of changes to git using git add, the file is then staged.
  • If a file has been changed and then staged via git add, then use git reset to pull the most recently committed version of the file and undo the changes that you’ve made.
    • git reset HEAD myFile.txt
      • This command unstages our changes. The HEAD refers to the most recently committed version of the file myFile.txt. You can also revert to an older version with HEAD-1, HEAD-2, etc.
  • When you use git reset, your changes still exist in the file, but the file has been unstaged, that is the changes are not added to git, yet.
    • You can confirm this with git status suggesting you to use git checkout to discard the changes in working directory.
      • git checkout -- myFile.txt

Undoing a commit

  • If you have modified, added and committed changes to a file, and want to undo the changes, then you can use git reset HEAD~ to undo your commit.
    • Confirm the status with git status . You’d notice that your file is no longer being tracked.
    • If you inspect the output of git log, you will notice that your previous commit is no longer part of the repo history.
    • Similar to previous example, when you use git reset the modifications will be unstaged. You need to git checkout -- to discard the changes.

Ignore sentitive files

  • If you do have sensitive files in a repo directory that you never want to track with git, you can add those file names to a file called .gitignore.

References

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