Linux commands

1. File and Directory Operations:

• ls: List files and directories.

• cd: Change directory.

• pwd: Print the working directory.

• mkdir: Create a new directory.

• rm: Remove files or directories. (Use with caution!)

• cp: Copy files or directories.

• mv: Move or rename files or directories.

• touch: Create an empty file.

• cat: Concatenate and display file content.

• nano or vim: Text editors for creating/editing files.

• find: Search for files and directories.

2. File Permissions:

• chmod: Change file permissions.

• chown: Change file ownership.

• chgrp: Change group ownership.

• umask: Set default permissions for new files and directories.

3. User and Group Management:

• useradd: Create a new user.

• usermod: Modify user properties.

• userdel: Delete a user.

• groupadd: Create a new group.

• groupmod: Modify group properties.

• groupdel: Delete a group.

4. Process Management:

• ps: Display running processes.

• top: Monitor real-time system activity.

• kill: Terminate processes.

• killall: Kill processes by name.

• bg: Put a process in the background.

• fg: Bring a process to the foreground.

5. System Information:

• uname: Display system information.

• df: Show disk space usage.

• free: Display free and used memory.

• du: Estimate file and directory space usage.

6. Networking:

• ifconfig or ip: Display network configuration.

• ping: Check network connectivity.

• netstat: Network statistics.

• ssh: Securely connect to remote servers.

• scp: Securely copy files between local and remote systems.

• wget or curl: Download files from the web.

• nslookup or dig: DNS-related commands.

7. Package Management:

• apt (Debian/Ubuntu) or yum (CentOS/RHEL): Install, update, and manage software packages.

• dpkg (Debian/Ubuntu) or rpm (CentOS/RHEL): Direct package management.

8. File Compression and Archiving:

• tar: Create and extract tar archives.

• gzip, bzip2, xz: Compress and decompress files.

9. System Maintenance:

• reboot: Reboot the system.

• shutdown: Shutdown the system.

• cron: Schedule tasks to run at specified times.

• journalctl: View system logs.

10. File System Management:

• mount and umount: Mount and unmount filesystems.

• fsck: File system check and repair.

Git commands

1. Git Configuration:

• git config --global user.name "Your Name": Set your username globally.

• git config --global user.email "youremail@example.com": Set your email globally.

• git config --global core.editor "editor": Set your preferred text editor for commit messages.

1. Creating and Cloning Repositories:

• git init: Initialize a new Git repository in the current directory.

• git clone <repository-url>: Clone a remote repository to your local machine.

1. Basic Git Workflow:

• git status: View the status of your working directory and staged changes.

• git add <file>: Stage changes for the next commit. Use git add . to add all changes.

• git commit -m "Your commit message": Commit staged changes with a descriptive message.

• git push origin <branch-name>: Push commits to a remote repository on a specific branch.

• git pull origin <branch-name>: Pull changes from a remote repository to your local branch.

• git fetch: Fetch changes from the remote repository without merging.

1. Branching and Merging:

• git branch: List all branches in the repository. The current branch is highlighted with an asterisk.

• git branch <branch-name>: Create a new branch with the specified name.

• git checkout <branch-name>: Switch to an existing branch.

• git checkout -b <new-branch-name>: Create a new branch and switch to it in one command.

• git merge <branch-name>: Merge the specified branch into the current branch.

• git rebase <branch-name>: Rebase the current branch onto the specified branch.

1. Viewing and Comparing Commits:

• git log: View the commit history.

• git log --oneline: View the commit history in a simplified one-line format.

• git show <commit-hash>: Show the details of a specific commit.

• git diff: View the changes between the working directory and the staging area.

• git diff --cached: View the changes between the staging area and the last commit.

1. Undoing Changes:

• git reset <file>: Unstaged changes from the staging area.

• git reset --hard: Discard all changes and revert to the last commit.

• git revert <commit-hash>: Create a new commit that undoes the changes introduced by the specified commit.

1. Remote Repositories:

• git remote add <remote-name> <remote-url>: Add a new remote repository.

• git remote -v: List all remote repositories.

• git push --set-upstream origin <branch-name>: Set the upstream branch for pushing and pulling.

• git pull --rebase: Pull changes and rebase the current branch instead of merging.

1. Miscellaneous:

• git stash: Stash your current changes to work on them later.

• git stash list: List all stashed changes.

• git stash apply: Apply the most recent stashed changes.

• git clean -n: Preview untracked files that will be removed with git clean -f.

• git blame <file>: Show the author and commit information for each line in a file.

Tip to remember:

Always be cautious when using administrative commands, especially those related to file deletion or system configuration. Double-check commands before executing them, and have proper backups in place.

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Happy learning :)