Essential Linux Commands for Everyday Use

Amaresh Pelleti

Linux commands serve as powerful tools for navigating the operating system, managing processes, and retrieving vital system information. Here’s a breakdown of essential commands categorized by function:

Files & Navigation

  1. ls: List files and directories in the current directory.
    • Example: ls -l displays detailed file information.
  2. cd: Change directory.
    • Example: cd /home/user/documents navigates to the “documents” directory.
  3. pwd: Print the current working directory.
    • Example: pwd shows the current directory path.
  4. mkdir: Create a new directory.
    • Example: mkdir new_folder creates a directory named “new_folder”.
  5. cp: Copy files and directories.
    • Example: cp file.txt destination_folder copies “file.txt” to the “destination_folder”.

Networking

  1. ping: Test network connectivity to a specific IP address.
    • Example: ping 8.8.8.8 checks connectivity to the Google DNS server.
  2. ifconfig: Display network interface information.
    • Example: ifconfig shows network interface details.
  3. ssh: Securely connect to a remote machine.
    • Example: ssh username@remote_host initiates an SSH connection.
  4. netstat: Display network statistics.
    • Example: netstat -tuln shows listening ports.
  5. curl: Transfer data from or to a server.
    • Example: curl example.com retrieves data from the specified URL.

Processes

  1. ps: Display information about active processes.
    • Example: ps aux shows all running processes.
  2. kill: Terminate processes by ID or name.
    • Example: kill PID terminates a process using its process ID.
  3. top: Display real-time system information and processes.
    • Example: top shows system statistics and running processes.
  4. killall: Terminate processes by name.
    • Example: killall process_name stops all processes with the given name.
  5. nice: Run a command with modified scheduling priority.
    • Example: nice -n 10 command runs a command with lower priority.

System Info

  1. uname: Display system information.
    • Example: uname -a shows kernel information.
  2. uptime: Show system uptime and load averages.
    • Example: uptime displays system uptime.
  3. free: Display system memory usage.
    • Example: free -m shows memory statistics in MB.
  4. df: Show disk space usage.
    • Example: df -h displays disk space in a human-readable format.
  5. lscpu: Display CPU information.
    • Example: lscpu shows detailed CPU information.

Permissions

  1. chmod: Change file permissions.
    • Example: chmod 755 file.txt grants read, write, and execute permissions to the file owner.
  2. chown: Change file owner.
    • Example: chown user:group file.txt changes the file’s owner and group.
  3. chgrp: Change group ownership of files.
    • Example: chgrp new_group file.txt changes the file’s group.
  4. ls -l: List files with detailed permissions.
    • Example: ls -l file.txt displays file permissions.

Other Commands

  1. grep: Search for specific patterns in files.
    • Example: grep "search_term" file.txt searches for “search_term” in the file.
  2. tar: Create or extract tar archives.
    • Example: tar -cvf archive.tar directory creates a tar archive.
  3. find: Search for files and directories.
    • Example: find / -name file.txt searches for “file.txt” in the root directory.
  4. man: Access the manual pages for commands.
    • Example: man command_name displays the manual for the specified command.
  5. echo: Display text on the terminal.
    • Example: echo "Hello, Linux!" prints the specified text.

Understanding and utilizing these fundamental Linux commands can significantly enhance your efficiency and productivity within the Linux environment.