Linux and Git-GitHub Cheat Sheet

here's a basic Linux file system commands cheat sheet:

Navigating the File System:

pwd: Print working directory (displays the current directory).

ls: List files and directories.

ls -l: Long format, shows detailed information.

ls -a: List all files, including hidden files.

ls -lh: Long format with human-readable file sizes.

cd: Change directory.

cd ..: Move to the parent directory.

cd ~: Move to the home directory.

mkdir: Create a new directory.

rmdir: Remove an empty directory.

Working with Files:

touch: Create an empty file.

cp: Copy files or directories.

cp source destination: Copy a file.

cp -r source destination: Copy a directory recursively.

mv: Move or rename files or directories.

rm: Remove files or directories.

rm file: Remove a file.

rm -r directory: Remove a directory and its contents recursively.

cat: Display the contents of a file.

more: Display the contents of a file page by page.

less: Display the contents of a file with backward navigation.

head: Display the beginning of a file.

tail: Display the end of a file.

nano or vim: Text editors to create and edit files.

File Permissions:

chmod: Change file permissions.

chown: Change file ownership.

Searching:

grep: Search for a pattern in files.

find: Search for files and directories.

sort: Sort lines of text files.

uniq: Display or filter duplicate lines in a file.

File Compression and Archiving:

tar: Create or extract tar archives.

tar -cvf archive.tar files: Create a tar archive.

tar -xvf archive.tar: Extract files from a tar archive.

gzip or gunzip: Compress or decompress files.

gzip file: Compress a file (creates .gz file).

gunzip file.gz: Decompress a compressed file.

Disk Usage:

df: Display disk space usage.

du: Display file and directory space usage.

du -h: Human-readable sizes.

du -sh directory: Summarize directory size.

Other:

ln: Create symbolic or hard links.

file: Determine file type.

mount and umount: Mount and unmount filesystems.

Managing Processes:
ps: Display information about currently running processes.

ps aux: Display detailed information about all processes.

ps -ef: Similar to ps aux, different syntax.

top:Display real-time system monitoring and process information.

htop: Interactive version of top with more features and controls.

pgrep: Search for processes by name.

Example: pgrep firefox to find the process ID of the Firefox browser.
pkill:Terminate processes by name.

Example: pkill firefox to terminate all Firefox processes.
kill: Send signals to processes (commonly used with process IDs).

kill -9 PID: Forcefully terminate a process with the given process ID.
killall: Terminate processes by name.

Example: killall chrome to terminate all Chrome browser processes.
nice and renice: Adjust process priority.

nice -n 10 command: Run a command with a lower priority (higher niceness value).

renice -n 5 -p PID: Change the priority of a running process.

Background and Foreground Execution:
&: Run a command in the background.

Example: command & runs command in the background.
jobs: List background jobs.

fg: Bring a background job to the foreground.

bg: Resume a suspended background job.

Process Control:
Ctrl+C: Interrupt (terminate) the currently running foreground process.

Ctrl+Z: Suspend the currently running foreground process.

nohup: Run a command that keeps running even after the terminal is closed.

Example: nohup command &.
System Monitoring and Logs:
uptime: Display system uptime and load average.

vmstat: Display virtual memory statistics.

dmesg: Display kernel ring buffer (boot messages).

sar: Collect and display system activity information.

iostat: Display I/O statistics.

Network Configuration:
ifconfig or ip addr: Display network interface information.

ifup interface_name: Bring a network interface up.

ifdown interface_name: Bring a network interface down.

ip link set interface_name up: Another way to bring an interface up.

ip link set interface_name down: Another way to bring an interface down.

ping host: Send ICMP echo request packets to a host.

traceroute host:Trace the route that packets take to reach a host.

Network Connectivity:
ping host: Check network connectivity to a host.

traceroute host: Display the path taken by packets to reach a host.

nslookup host: Perform DNS lookups to retrieve IP addresses.

dig host: Another tool to query DNS information.

host host: Display DNS information.

Networking and Transfers:
wget: Download files from the internet.

curl: Transfer data to/from servers.

Network Diagnostics:
netstat: Display network statistics (deprecated; use ss instead).

ss: Display socket statistics.

nmap host: Perform network scanning to discover open ports and services.

arp: Display and manipulate the ARP cache.

iftop: Display bandwidth usage on an interface.

iftop -i interface_name: Monitor bandwidth of a specific interface.

Firewall and Security:
ufw: Uncomplicated Firewall management tool.

iptables: Powerful tool for configuring firewall rules.

Package Management:

Debian-based Distributions (e.g., Ubuntu):

apt-get update: Update the package list.

apt-get upgrade: Upgrade installed packages.

apt-get install package_name: Install a package.

apt-get remove package_name: Remove a package (keeps configuration files).

apt-get purge package_name: Completely remove a package (including configuration files).

apt-cache search keyword: Search for packages.

apt-cache show package_name: Display package information.

dpkg -i package.deb: Install a package from a .deb file.

dpkg -r package_name: Remove a package.

dpkg -l: List all installed packages.

Red Hat-based Distributions (e.g., CentOS):

yum update:Update installed packages.

yum install package_name: Install a package.

yum remove package_name: Remove a package.

yum search keyword: Search for packages.

yum info package_name: Display package information.

rpm -ivh package.rpm: Install a package from an .rpm file.

rpm -e package_name: Remove a package.

rpm -qa: List all installed packages.

Common for Both:
apt (Ubuntu) / yum (CentOS): Package managers to manage software.

snap: Package manager for installing and managing snap packages.

dnf: Modern package manager replacing yum in newer Fedora distributions.

Git and GitHub Cheat Sheet: Key Operations
Cloning a Repository:
git clone <repository_url>:Clone a remote repository to your local machine.
Basic Workflow:
Checking Status:

git status: Check the status of your working directory and staged changes.
Adding Changes:

git add <file>: Stage a specific file for commit.

git add . or git add -A: Stage all changes for commit.

Committing Changes:

git commit -m "Your commit message": Commit staged changes with a message.
Pushing Changes:

git push origin <branch>: Push committed changes to a remote branch.
Branching and Merging:
Creating and Switching Branches:

git branch: List all branches.

git branch <new_branch>: Create a new branch.

git checkout <branch>: Switch to an existing branch.

Merging Branches:

git merge <branch_to_merge>: Merge changes from another branch into the current branch.
Pulling Changes:
git pull origin <branch>: Fetch and merge remote changes into your local branch.

Inspecting History:
git log: Display commit history.

git log --oneline: Display compact commit history.

git diff: Show differences between working directory and staging area.

git diff --staged: Show differences between staging area and last commit.

Remote Repositories:
git remote -v: List remote repositories.

git remote add <name> <repository_url>: Add a new remote repository.

git remote remove <name>:Remove a remote repository.

git push origin -d <branch-name> : Delete remote branch

Undoing Changes:
git reset <file>: Unstage changes from a file.

git checkout -- <file>: Discard changes in a file.

git revert <commit>: Create a new commit that undoes changes of a previous commit.

Resetting Commits:
git reset --soft <commit>: Move the branch pointer to a specific commit, keeping changes staged.

git reset --mixed <commit> (default behavior): Move the branch pointer and unstage changes, preserving changes in working directory.

git reset --hard <commit>: Move the branch pointer, unstage changes, and discard changes in working directory.

Ignoring Files:
Create a .gitignore file in the repository to list files and patterns to be ignored.
Renaming and Deleting:
git mv <old_file_name> <new_file_name>: Rename a file.

git rm <file>: Delete a file.

Remote Collaboration:
git clone <repository_url>: Clone a remote repository.

git fetch: Fetch changes from a remote repository.

git pull origin <branch>: Fetch and merge remote changes.

git push origin <branch>: Push changes to a remote branch.

Removing Untracked Files:
git clean -n: List untracked files that will be removed.

git clean -f: Remove untracked files from the working directory.

Stashing Changes:
git stash: Stash your changes (both staged and unstaged).

git stash save "message": Stash changes with a descriptive message.

Listing Stashes:
git stash list: List all stashes with their IDs and messages.
Applying Stashes:
git stash apply: Apply the most recent stash and keep it in the stash list.

git stash apply stash@{n}: Apply a specific stash by its index.

Popping Stashes:
git stash pop: Apply and remove the most recent stash.

git stash pop stash@{n}: Apply and remove a specific stash by its index.

Dropping Stashes:
git stash drop stash@{n}: Remove a specific stash by its index.

git stash clear: Remove all stashes.