Useful and common git commands for newbie programmer (feat. ssh-agent)

In this post, I assume your ssh key was already registered in your git hosting service such as Github, bitbucket, etc. If you don't know how to generate a new ssh key, you can search from your favourite search engine by typing  a search keyword like github(or other alternative) generate ssh key

Just in case, I leave a page link for Github and Bitbucket in regards to this ssh key

• Github
• BitBucket

Ok. Let's start!

Here are some useful commands that I am personally using often on my day-to-day works. First, to avoid any authentication issue with your git hosting service, start with ssh agent.

• Start ssh agent

eval $(ssh-agent -s)

• Add your private key

Please make sure to use the private key (file without having file extension such as ".pem" or ".ppk")

ssh-add yourpathtoprivatekey

For example, if your key is located under .ssh folder, then the command can be

ssh-add ~/.ssh/iamprivatekey

• Check list of keys

ssh-add -l

If your key is successfully added, then you should not see the "The agent has no identities." message

• Check your current branch

git branch

This will show the list of branch you have checked out. The current working branch will have the asterisk(*) in front of a branch name (e.g. * develop)

• Create new branch

If you need to make a code update on brand new branch, the use

git checkout -b new-branch-name

This will create the new branch and switch your current branch to the new branch.

• Switch your branch

If you or your team member already create a new branch from your git hosting service and you need to switch your branch, then use this command.

git fetch && git checkout new-branch

• Display the state of your working project directory

git status

This command will show you the list of files that have been modified, but show them into three different groups: staged, non-staged, untracked. Staged files are one will be committed.  Non-staged files are simply files that are not staged for commit yet. Untracked files are the one not being tracked by Git.

• Add a file for commit

# Add your file to be staged
# Use git add yourfilepath
git add /src/main/java/com/test1/filetocommit.java

# If you want to add every file under test1 folder
git add /src/main/java/com/test1

Git status command after this will allow you to see the list of staged files in green text.

• Unstage a file

If you add a file by mistake and want to unstage, you can run

git restore --staged woops-not-this-file.java

• Discard your change of one file

git checkout yourfilepath/to/restore/back/to/original.java

• Commit your changes

Once you finish adding all files that you want to commit, run the following command.

git commit -m "Describe your changes in this double quotes, do not forget"

• Push your commit to your git repository

git push

• Merge one branch to the other branch

#Assume your working branch is called "feature-test"
git merge branch-name-that-you-want-to-merge

#For example, you want to merge to develop branch
git merge develop

However, merging branches wouldn't happen that often if you are working with other team members. In this case, a typical process would be as follows.

1. Create a PR (Pull Request) from your Git hosting service
2. Add your team member as a reviewer
3. Team member review your PR and leave a feedback if needed
4. Team member approve your PR
5. Merge branch from your PR

So, in this post, I covered

• how to start ssh-agent and add the key to get proper authentication from your Git hosting service.
• how to use common git commands.

Hope this can be useful for someone. Happy coding!