1. File System Navigation:

• pwd: Print the current working directory.

• ls: List files and directories in the current directory.

  • ls -l: Display detailed information about files and directories.

  • ls -a: Include hidden files and directories in the list.

• cd directory: Change the current directory to the specified directory.

  • cd ..: Go up one level in the directory hierarchy.

  • cd ~: Go to the home directory.

• mkdir directory: Create a new directory with the specified name.

• rm file: Remove a file.

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

• cp source destination: Copy a file or directory.

  • cp -r source destination: Copy a directory and its contents recursively.

• mv source destination: Move or rename a file or directory.

2. File Manipulation:

• cat file: Display the contents of a file.

• less file: View the contents of a file with pagination.

• head file: Display the first few lines of a file.

• tail file: Display the last few lines of a file.

• grep pattern file: Search for a pattern in a file.

  • grep -r pattern directory: Recursively search for a pattern in files within a directory.

3. File Permissions:

• chmod permissions file: Change the permissions of a file or directory.

  • chmod +x file: Add executable permission to a file.

  • chmod -w file: Remove write permission from a file.

• chown user:group file: Change the owner and group of a file or directory.

• chgrp group file: Change the group of a file or directory.

4. Process Management:

• ps: Display information about active processes.

  • ps -ef: Display detailed information about all processes.

• kill process_id: Terminate a process with the specified process ID.

  • killall process_name: Terminate all processes with the specified name.

• top: Display real-time information about system processes.

• bg: Put a process in the background.

• fg: Bring a background process to the foreground.

5. System Information:

• uname: Print system information.

  • uname -a: Print detailed system information.

• whoami: Display the current user.

• df: Show disk space usage.

• free: Display memory usage.

• uptime: Show system uptime.

• ifconfig: Display network interface information.

• ping host: Send ICMP echo requests to a host for network connectivity testing.

6. Text Editing:

• nano file: Open a file for editing with the Nano editor.

• vi file: Open a file for editing with the Vi editor.

• grep pattern file: Search for a pattern in a file.

  • grep -r pattern directory: Recursively search for a pattern in files within a directory.

• sed 's/old/new/g' file: Replace occurrences of a pattern with a new value in a file

7. Compression and Archiving:

• tar cf archive.tar files: Create a tar archive of specified files.

• tar xf archive.tar: Extract files from a tar archive.

• gzip file: Compress a file using gzip compression.

  • gzip -d file.gz: Decompress a file compressed with gzip.

8. Networking:

• ssh user@host: Connect to a remote host using SSH.

• scp source destination: Securely copy files between local and remote hosts.

• wget url: Download a file from a specified URL.

• curl url: Transfer data to or from a server using various protocols.

9. User Management:

• useradd username: Create a new user account.

• userdel username: Delete a user account.

• passwd username: Set or change the password for a user account.

• su username: Switch to another user account.

• sudo command: Execute a command with superuser (root) privileges.

10. Package Management:

• apt-get install package: Install a package using the Advanced Package Tool (APT) package manager.

• apt-get update: Update the local package index to retrieve the latest package information.

• apt-get upgrade: Upgrade all installed packages to their latest versions.

• apt-get remove package: Uninstall a package.

• apt-cache search keyword: Search for packages based on a keyword.

11. File Transfer:

• scp source destination: Securely copy files between local and remote hosts using the SSH protocol.

• rsync source destination: Synchronize files and directories between local and remote hosts efficiently.

• sftp user@host: Start an interactive secure file transfer session with a remote host.

12. System Monitoring and Maintenance:

• top: Monitor system processes and resource usage in real-time.

• htop: Interactive process viewer and system monitor.

• du -sh directory: Display the total size of a directory.

• df -h: Show disk space usage of mounted file systems.

• reboot: Reboot the system.

• shutdown: Shutdown the system.

13. Networking and Connectivity:

• ifconfig: Configure and display network interface information.

• ping host: Send ICMP echo requests to a host for network connectivity testing.

• netstat: Display network connection information, routing tables, and interface statistics.

• ssh user@host: Connect to a remote host using SSH.

• nc host port: Open a TCP or UDP connection to a remote host on a specified port.

14. System Information:

• uname -a: Display detailed system information including the kernel version.

• lsb_release -a: Show distribution-specific information about the Linux distribution.

• hostname: Print or set the system's hostname.

• date: Display the current date and time.

15. File Permissions and Ownership:

• chmod permissions file: Change the permissions of a file or directory.

• chown user:group file: Change the owner and group of a file or directory.

• chgrp group file: Change the group of a file or directory.

• ls -l: List files and directories with detailed permission and ownership information.

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