Basic Introduction to Git (Part 2)

Initialising a Repository in an Existing Directory

If you wish to have a project directory under version control with GIt, do the following

$ cd /home/user/my_project
$ git init

If you wish to add existing files into the version control

$ git add *.sh
$ git add LICENSE
$ git commit --m "Gekko Menu Help Application"
[master (root-commit) c98ae91] Gekko Menu Help Application
 1 file changed, 73 insertions(+)
 create mode 100755 mymenu.sh

You have an initial commit and tracked files. Hooray.

Checking the status of your Files

[user1@node1 menu]$ git status
# On branch master
nothing to commit, working directory clean

This means you have a clean working directory; in other words, none of your tracked files are modified.

Adding new files to your Git Directory

Let’s say you added a new file called check_license_abaqus.sh into the Project Directory, you will have something like

# On branch master
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       check_license_abaqus.sh
nothing added to commit but untracked files present (use "git add" to track)

To add files

[user1@node1 menu]$ git add check_license_abaqus.sh
[user1@node1 menu]$ git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#       new file:   check_license_abaqus.sh
#

To remove file

[user1@node1 menu]$ git rm check_license_abaqus.sh -f
rm 'check_license_abaqus.sh'
[user1@node1 menu]$ git status
# On branch master
nothing to commit, working directory clean

To see log, you want to use the command

[user1@node1 menu]$ git log
commit xxxxxxxxx
Author: user1 <kmyemail_used_in_Github@hotmail.com>
Date:   Sun Sep 25 23:50:33 2022 +0800

    Gekko Menu Help Application

There are many more usage. For more information, do take a look at 2.3 Git Basics – Viewing the Commit History

References:

  1. 2.2 Git Basics – Recording Changes to the Repository
  2. 2.3 Git Basics – Viewing the Commit History
  3. 2.4 Git Basics – Undoing Things

Basic Introduction to GitHub (Part 1)

GitHub is the largest code-hosting platform in the world. It uses Git as version control and the repository is based on GitHub. Features such as Pull Requests, Project Boards and GitHub are central and found in one place.

Sign up for a Free Account

To start using GitHub, please go to https://github.com/join and follow the instruction

Creating a PAT of SSH Key

A PAT is a string of characters that can be used in place of a password against the GitHub API and on command lone.

You may need to understand the various scopes on GitHub such as repo, admin: repo_hook, users etc. For more information, do take a look at https://docs.github.com/en/developers/apps/building-oauth-apps/scopes-for-oauth-apps#available-scopes

For starters, you may want to go to https://github.com/settings/tokens and click on Generate new token

On Linux, you can generate your SSH key using the email that you have created in your GitHub User Account

[user1@node1 ~]$ ssh-keygen -t rsa -C "myemail_used_in_Github@hotmail.com"
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user1/.ssh/id_rsa):
/home/user1/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/user1/.ssh/id_rsa.
Your public key has been saved in /home/user1/.ssh/id_rsa.pub.
The key fingerprint is:
........
........

Adding the SSH Key to the ssh-agent

Although this is not mandatory, adding the SSH Key to the SSH Agent is a good practice that will keep the SSH Key safe. The SSH-agent is an SSH Key Manager that helps to keep the SSH key safe because it protects your SSH keys from being exported. The SSH Agent also saves you from having to type the passphrase you create. every time your SSH key is used.

Before you check, you want to check your ~/.ssh/config first

$ vim ~/.ssh/config
Host * 
AddKeysToAgent yes

At the Terminal,

$ ssh-add ~/.ssh/id_rsa

Copy your SSH Public Key to the field. In your ~/.ssh/config, it should have a .pub extension like id_rsa.pub

Configuring Git

To intialise the Git. Do the following. You may want to take a look at

[user1@node1 ~]$ git config --global user.name "Melvin Soh"
[user1@node1 ~]$ git config --global user.email "kittycool@hotmail.sg"
[user1@node1 ~]$ git config --global init.defaultBranch main
[user1@node1 ~]$ git config --list
credential.helper=netrc -f ~/.netrc.gpg -v
user.name=user1
user.email=myemail_used_in_Github@hotmail.com
init.defaultbranch=main

To continue, See Basic Introduction to GitHub (Part 2)

References:

  1. 1.5 Getting Started – Installing Git
  2. 1.6 Getting Started – First-Time Git Setup