Git/Github is the most popular version control system. I also use it to manage my projects as well as to collaborate with others. In this post, I will summarize some basic/important git commands.

How to clone a github repo to local computer?

git clone REPO_URL

How to upload local changes to remote repo?

git add FILE
git commit -m "message"
git push

How to collaborate with others using forking?

• Firstly, fork an existing repo to get a forked copy in your private account.
• Next, use git clone to create a local copy of your forked repo.
• Run below command to link local repo to the original upstream repo.
  git remote add upstream <original_repo_URL>
• Then, edit local copy (add/modify/delete files).
• After that, use above command to upload local changes to your remote forked repo.
• Lastly, on your remote forked repo, create a pull request, so that your collaborators can get a notification, review the changes you made, and merge them.

If others made changes and sent a pull request:

• You firstly need to review these changes on github and merge it.
• Then, run below command to sync your local repo and your remote forked repo.
  git fetch upstream
git merge upstream/master
git push

How to collaborate with others using branching?

• Firstly, clone the remote project repo to local.
  git clone REPO_URL
• Create a new branch locally and switch to this new branch.
  git branch BRANCH_NAME
git checkout BRANCH_NAME
• After making some changes (add/modify/delete files), push.
  git add FILE_NAME
git commit -a -m "MESSAGE"
git push -u origin BRANCH_NAME
• Then, on github project repo, create a pull request, so that your collaborators can review the changes you have made.
• After your collaborators reviewed and merged your pull request on github, you need to update your local master:
  git checkout master
git pull
• If you don’t need your collaborators to review and merge on github, you can, after commit your changes, merge your branch locally:
  git add FILE_NAME
git commit -a -m "MESSAGE"
git checkout master
git merge BRANCH_NAME
git add .
git commit -a -m "MESSAGE"
git push
• If your collaborators make some changes to the master branch and you want to incorporate all the changes to your local branch, you should use below command:
  git pull origin master
• If you made some change on a local branch and decided you want to discard the change:
  git checkout -- filename
• For a branch that has been pushed and merged into master, you can delete it:
  git branch -d BRANCH_NAME

Other useful branching command:
git log --oneline --decorate # check where the branch pointers are pointing
git branch # show the list of all available branches
git branch -v # show the last commit on each branch
git branch --merged # show all branches that have been merged. You can delete merged branches later on
git branch --no-merged # show all branches that have not been merged.