🐧 The Ultimate Linux & Git-GitHub Cheat Sheet for DevOps 🛠️
Tech enthusiast | Code craftsman | DevOps explorer | Turning bugs into features one line at a time 🚀
This cheat sheet will cover Linux commands, Git commands, and GitHub essentials, with descriptions, examples, and real-world relevance.
🐧 Linux Commands for Everyday Use
| Command | Description | Example |
whoami | Displays the current logged-in user. | whoami |
uname -r | Displays the Linux kernel version. | uname -r |
df -h | Shows disk usage in a human-readable format. | df -h |
du -sh [directory] | Shows the size of a directory or file. | du -sh /home/user |
ls -la | Lists all files and directories with detailed information. | ls -la |
pwd | Prints the current working directory. | pwd |
mkdir [directory] | Creates a new directory. | mkdir project_folder |
rm -rf [directory/file] | Deletes files or directories (use with caution). | rm -rf old_files |
chmod [permissions] [file] | Changes file permissions. | chmod 755 script.sh |
chown [user]:[group] [file] | Changes ownership of a file or directory. | chown user:group file.txt |
ps -aux | Displays all running processes. | ps -aux |
kill [process_id] | Terminates a process by its PID. | kill 1234 |
history | Shows command history. | history |
alias [name]='[command]' | Creates a shortcut for a command. | alias ll='ls -la' |
curl [url] | Fetches data from a URL. | curl https://example.com |
wget [url] | Downloads a file from a URL. | wget https://example.com/file.zip |
scp [file] [user@host:/path] | Securely copies files between local and remote systems. | scp file.txt user@192.168.1.1:/tmp |
ssh [user@host] | Connects to a remote server via SSH. | ssh user@192.168.1.1 |
🔍 Text Processing Commands.
| Command | Description | Example |
find [directory] -name "[name]" | Searches for files by name. | find /home -name "*.txt" |
awk '/pattern/ {action}' [file] | Processes text based on patterns in files. | awk '/error/ {print $2}' log.txt |
sed -i 's/[old]/[new]/g' [file] | Finds and replaces text in a file. | sed -i 's/foo/bar/g' file.txt |
sort [file] | Sorts lines in a file. | sort data.txt |
uniq [file] | Removes duplicate lines from a file. | uniq data.txt |
wc -l [file] | Counts the number of lines in a file. | wc -l file.txt |
grep [pattern] [file] | Searches for a pattern in a file. | grep "error" log.txt |
crontab -e | Edits the crontab to schedule recurring tasks. | crontab -e |
🌐 Networking Commands
| Command | Description | Example |
ping [host] | Tests connectivity to a server. | ping google.com |
netstat -tuln | Displays open ports and network connections. | netstat -tuln |
ip a | Displays IP address and network details. | ip a |
scp [file] [user@host:/path] | Copies files between local and remote systems. | scp backup.zip user@192.168.1.1:/tmp |
ssh [user@host] | Connects to a remote server via SSH. | ssh user@192.168.1.1 |
curl -I [url] | Fetches HTTP headers for a URL. | curl -I https://example.com |
🛠️ Git Essentials
| Command | Description | Example |
git init | Initializes a Git repository in the current directory. | git init |
git clone [url] | Creates a local copy of a remote repository. | git clone https://github.com/user/repo.git |
git status | Shows the status of changes in the working directory. | git status |
git add [file] | Stages a file for commit. | git add README.md |
git commit -m "[message]" | Saves staged changes with a commit message. | git commit -m "Initial commit" |
git push origin [branch] | Pushes changes to the remote repository. | git push origin main |
git pull origin [branch] | Fetches and merges changes from a remote repository. | git pull origin main |
git branch | Lists all branches in the repository. | git branch |
git checkout -b [branch] | Creates and switches to a new branch. | git checkout -b feature-branch |
git merge [branch] | Merges a branch into the current branch. | git merge feature-branch |
git log | Displays the commit history. | git log |
🌟 GitHub Essentials
| Action | Description | Steps |
| Create a Repository | Sets up a new repository on GitHub. | Go to GitHub → Click on "New" → Fill details. |
| Clone a Repository | Copies an existing repository to your local system. | git clone [url] |
| Push Changes | Updates the remote repository with local changes. | git push origin main |
| Pull Requests | Proposes changes to a branch. | Navigate to your branch → Click "Pull Request". |
Introduction
In the world of DevOps, Git and GitHub are essential tools that help developers work together and manage their code.
What is Git?🌿🐱
Definition: Git is a distributed version control system that helps developers track changes in their code, collaborate with others, and manage software development efficiently.
Key Aspects of Git:
Version Control: Tracks code changes effectively.
Branching: Isolates different feature developments.
Collaboration: Enables smooth teamwork and contributions.
Remote repositories facilitate easy code sharing and backups.
Pull Requests: Allow code review before merging.
Fundamental Concepts in Git:
Commits: Snapshots of code changes.
Repositories: Collection of code and history.
Working Directory: Where developers make changes.
Staging Area: Prepares changes for commits.
Push and Pull: Sending and fetching changes.
Merge and Conflict Resolution: Combining changes and handling conflicts.
Branches: Separate development paths for features.
Forks: Personal copies for independent development.
What is GitHub?
Definition: GitHub is a web-based hosting service that uses Git for version control. It provides a platform for developers to store, manage, and collaborate on code repositories.
Key Aspects:
Code Hosting: Store code online.
Collaboration: Work together on projects.
Community and Open Source: Global developer community.
Issue Tracking: Manage project issues.
CI/CD Integration: Automate testing and deployment.
What is Version Control? How many types of version controls we have?
Version control is a system that helps you manage changes to your files and code over time. It keeps track of different versions of your work, allowing you to go back to previous states, collaborate with others, and avoid conflicts. It's like having a time machine for your project, so you can undo mistakes and track progress.
There are mainly two types of version control:
Centralized Version Control (CVC): In CVC, there is a central server that stores all the project files and their versions. When team members want to work on the project, they check out a copy from the central server, make changes, and then commit those changes back to the server. Examples of CVC systems include Apache Subversion (SVN) and Perforce.
Distributed Version Control (DVC): DVC, on the other hand, doesn't rely on a central server. Each team member has a complete copy of the entire project, including its history. They can work independently and synchronize their changes directly with each other. Examples of DVC systems include Git and Mercurial.
CVCS vs DVCS
| Sr. No. | Key | Centralized Version Control | Distributed Version Control |
| 1 | Working | In CVS, a client need to get local copy of source from server, do the changes and commit those changes to centeral source on server. | In DVS, each client can have a local branch as well and have a complete history on it. Client need to push the changes to branch which will then be pushed to server repository. |
| 2 | Learning Curve | CVS systems are easy to learn and set up. | DVS systems are difficult for beginners. Multiple commands needs to be remembered. |
| 3 | Branches | Working on branches in difficult in CVS. Developer often faces merge conflicts. | Working on branches in easier in DVS. Developer faces lesser conflicts. |
| 4 | Offline Access | CVS system do not provide offline access. | DVD systems are workable offline as a client copies the entire repository on their local machine. |
| 5 | Speed | CVS is slower as every command need to communicate with server. | DVS is faster as mostly user deals with local copy without hitting server everytime. |
| 6 | Backup | If CVS Server is down, developers cannot work. | If DVS server is down, developer can work using their local copies. |
Setting Up Your Local Repository:
Install Git on your computer.
Click here for download git in your systemConfigure your name and email in Git.
username:
git config --global user.name "Your Name"Email:
git config --globaluser.email "your.email@example.com"
Open the terminal or command prompt.
Navigate to the directory where you want to create your repository.
Initialize a new Git repository using
git init.Add your files to the staging area with
git add.Make your first commit using
git commit.Create a remote repository on GitHub (optional).
Link your local repository to the remote one using
git remote add origin.Push your code to the remote repository with
git push origin.
Your local repository is now set up and ready to track changes and collaborate with others using Git.
Git Commands
git init: Initializes a new Git repository in the current directory.git add <file_name>: Stages (adds) a file to be included in the next commit. Usegit add .to stage all changes.git status: Shows the current status of your working directory, including modified files and staged changes.git log: Displays the commit history, showing the commit IDs, authors, dates, and commit messages.git diff: Compare changes between files, showing line-by-line differences between versions.git commit -m "Commit message": Creates a new commit with the changes that you have staged. The commit message should briefly describe the changes made.git branch: Lists all branches in the repository. Usegit branch <branch_name>to create a new branch.git checkout <branch_name>: Switches to a different branch.git merge <branch_name>: Merges changes from a different branch into the current branch.git clone <repository_url>: Clones (downloads) a remote repository to your local machine.git pull: Fetches and merges changes from the remote repository into your local branch.git push: Pushes your local commits to the remote repository.git stash: Temporarily saves changes for later use without committing.git cherry-pick: Applies a specific commit from one branch to another.
