In the ever-evolving world of Linux, where the command line reigns supreme, reviewing Linux commands periodically is like honing the edge of a mighty sword. It’s the secret sauce that keeps your skills sharp, your fingertips nimble, and your sysadmin game strong. Because let’s face it, constantly referring to documentation is like navigating a maze blindfolded—frustrating and time-consuming.
So, embrace the wisdom of the penguin, my friends, and make it a habit to revisit those command-line gems. Unleash the power of your terminal, bask in the elegance of one-liners, and command your Linux kingdom with confidence. Trust me, your fellow geeks will marvel at your mastery, and you’ll be the hero of the command line universe.
These commands are commonly used in Linux systems and cover a wide range of tasks, including file management, process management, system administration, network configuration, and more.
1. ls - List directory contents Example: `ls -l` (List files in long format) 2. cd - Change directory Example: `cd /path/to/directory` (Change to a specific directory) 3. pwd - Print working directory Example: `pwd` (Display the current directory path) 4. mkdir - Make directory Example: `mkdir new_directory` (Create a new directory) 5. rm - Remove files or directories Example: `rm file.txt` (Delete a file) 6. cp - Copy files and directories Example: `cp file.txt destination/` (Copy a file to a destination) 7. mv - Move or rename files and directories Example: `mv file.txt new_name.txt` (Rename a file) 8. touch - Create an empty file Example: `touch file.txt` (Create a new empty file) 9. cat - Concatenate and display file content Example: `cat file.txt` (Display the content of a file) 10. grep - Search for patterns in files Example: `grep "pattern" file.txt` (Search for a specific pattern in a file) 11. find - Search for files and directories Example: `find /path/to/directory -name "filename"` (Find a specific file in a directory) 12. chmod - Change file permissions Example: `chmod 755 file.txt` (Change the permissions of a file) 13. chown - Change file ownership Example: `chown user:group file.txt` (Change the ownership of a file) 14. tar - Archive files and directories Example: `tar -czvf archive.tar.gz directory/` (Create a compressed archive of a directory) 15. unzip - Extract files from a ZIP archive Example: `unzip archive.zip` (Extract files from a ZIP file) 16. ssh - Secure shell remote login Example: `ssh username@hostname` (Connect to a remote server using SSH) 17. sudo - Execute a command with superuser privileges Example: `sudo apt update` (Update package lists using sudo) 18. apt-get - Package handling utility for Debian-based systems Example: `apt-get install package_name` (Install a package using apt-get) 19. man - Display the manual page of a command Example: `man ls` (Display the manual for the "ls" command) 20. ps - Display running processes Example: `ps aux` (Display all running processes) 21. top - Display system resource usage Example: `top` (Monitor system resource utilization) 22. du - Estimate file and directory space usage Example: `du -sh directory/` (Show the total size of a directory) 23. df - Display disk space usage Example: `df -h` (Display disk space usage in a human-readable format) 24. ping - Send ICMP echo requests to a network host Example: `ping google.com` (Ping a website to check network connectivity) 25. ifconfig - Configure network interfaces Example: `ifconfig eth0 up` (Bring up a network interface) 26. wget - Retrieve files from the web Example: `wget http://example.com/file.txt` (Download a file from a URL) 27. curl - Transfer data to or from a server Example: `curl http://example.com` (Retrieve the contents of a web page) 28. systemctl - Control the systemd system and service manager Example: `systemctl start service_name` (Start a system service) 29. journalctl - Query the systemd journal Example: `journalctl -u service_name` (View the logs of a specific service) 30. scp - Securely copy files between hosts Example: `scp file.txt user@host:/path/to/destination` (Copy a file to a remote host) 31. grep -r - Search for text recursively in files and directories Example: `grep -r "pattern" directory/` (Search for a pattern recursively in a directory) 32. sed - Stream editor for filtering and transforming text Example: `sed 's/foo/bar/' file.txt` (Replace occurrences of "foo" with "bar" in a file) 33. awk - Text processing and pattern scanning language Example: `awk '{ print $1 }' file.txt` (Print the first column of a file) 34. ssh-keygen - Generate SSH key pairs Example: `ssh-keygen -t rsa` (Generate an RSA SSH key pair) 35. systemctl status - Display the status of a systemd unit Example: `systemctl status service_name` (Check the status of a service) 36. diff - Compare files line by line Example: `diff file1.txt file2.txt` (Compare two files and show the differences) 37. head - Output the first part of files Example: `head -n 10 file.txt` (Display the first 10 lines of a file) 38. tail - Output the last part of files Example: `tail -n 5 file.txt` (Display the last 5 lines of a file) 39. tar -xvf - Extract files from a tar archive Example: `tar -xvf archive.tar` (Extract files from a tar archive) 40. history - Display the command history Example: `history` (Show a list of previously executed commands) 41. ln - Create links between files Example: `ln -s file.txt link.txt` (Create a symbolic link to a file) 42. mount - Mount a file system Example: `mount /dev/sda1 /mnt` (Mount a partition to a mount point) 43. umount - Unmount a file system Example: `umount /mnt` (Unmount a mounted file system) 44. chmod +x - Make a file executable Example: `chmod +x script.sh` (Make a script executable) 45. grep -v - Invert match and exclude lines matching a pattern Example: `grep -v "pattern" file.txt` (Print lines not containing the pattern) 46. kill - Terminate a process Example: `kill process_id` (Terminate a process by its ID) 47. systemctl enable - Enable a systemd unit to start on boot Example: `systemctl enable service_name` (Enable a service to start automatically) 48. chown -R - Change ownership recursively Example: `chown -R user:group directory/` (Change the ownership of a directory and its contents) 49. useradd - Create a user account Example: `useradd username` (Create a new user account) 50. usermod - Modify user account properties Example: `usermod -aG groupname username` (Add a user to a group) 51. passwd - Change user password Example: `passwd username` (Change the password for a user) 52. systemctl restart - Restart a systemd unit Example: `systemctl restart service_name` (Restart a service) 53. sort - Sort lines of text files Example: `sort file.txt` (Sort the lines of a file alphabetically) 54. which - Locate the executable of a command Example: `which command` (Find the location of a command's executable) 55. crontab - Schedule periodic tasks Example: `crontab -e` (Edit the user's crontab file) 56. ssh-key-copy - Copy SSH public key to a remote server Example: `ssh-copy-id user@host` (Copy SSH public key to a remote server) 57. ln -s - Create a symbolic link Example: `ln -s /path/to/file link_name` (Create a symbolic link to a file) 58. history -c - Clear command history Example: `history -c` (Clear the command history) 59. alias - Create an alias for a command Example: `alias l='ls -l'` (Create an alias "l" for the "ls -l" command) 60. echo - Print a message Example: `echo "Hello, World!"` (Print the message "Hello, World!") 61. systemctl stop - Stop a systemd unit Example: `systemctl stop service_name` (Stop a service) 62. gzip - Compress files Example: `gzip file.txt` (Compress a file using gzip) 63. gunzip - Decompress files compressed with gzip Example: `gunzip file.txt.gz` (Decompress a file compressed with gzip) 64. tar -cvf - Create a tar archive Example: `tar -cvf archive.tar directory/` (Create a tar archive of a directory) 65. tar -tvf - View the contents of a tar archive Example: `tar -tvf archive.tar` (List the files in a tar archive) 66. df -h - Display disk space usage in a human-readable format Example: `df -h` (Show disk space usage in a human-readable format) 67. df -i - Display inode usage Example: `df -i` (Display inode usage) 68. ifconfig -a - Display all network interfaces Example: `ifconfig -a` (Display all network interfaces) 69. netstat -tuln - Display listening ports Example: `netstat -tuln` (Show listening ports) 70. systemctl reload - Reload a systemd unit configuration Example: `systemctl reload service_name` (Reload a service configuration) 71. systemctl disable - Disable a systemd unit from starting on boot Example: `systemctl disable service_name` (Disable a service from starting automatically) 72. free -m - Display memory usage in megabytes Example: `free -m` (Show memory usage in megabytes) 73. ps -ef - Display a snapshot of the current processes Example: `ps -ef` (Display all running processes) 74. ssh-keygen -p - Change passphrase of an SSH private key Example: `ssh-keygen -p` (Change the passphrase of an SSH private key) 75. history -w - Write the current history to the history file Example: `history -w` (Write the current history to the history file) 76. find -type f -name - Search for files with a specific name Example: `find /path/to/directory -type f -name "filename"` (Search for a file by name) 77. locate - Find files by name Example: `locate file.txt` (Find the path of a file by name) 78. systemctl list-units - List all systemd units Example: `systemctl list-units` (List all active systemd units) 79. cat file1.txt file2.txt - Concatenate multiple files and display the content Example: `cat file1.txt file2.txt` (Concatenate the content of two files) 80. grep -i - Perform a case-insensitive pattern search Example: `grep -i "pattern" file.txt` (Search for a pattern case-insensitively) 81. chmod -R - Change permissions recursively Example: `chmod -R 755 directory/` (Change the permissions of a directory and its contents recursively) 82. wc -l - Count the number of lines in a file Example: `wc -l file.txt` (Count the number of lines in a file) 83. tail -f - Output the last part of a file and follow its changes Example: `tail -f file.txt` (Display the last part of a file and follow new lines as they are appended) 84. chgrp - Change group ownership Example: `chgrp groupname file.txt` (Change the group ownership of a file) 85. gzip -d - Decompress files compressed with gzip Example: `gzip -d file.txt.gz` (Decompress a file compressed with gzip) 86. tar -xvf - Extract files from a tar archive Example: `tar -xvf archive.tar` (Extract files from a tar archive) 87. awk '{print $NF}' - Print the last field of each line Example: `awk '{print $NF}' file.txt` (Print the last field of each line in a file) 88. sort -r - Sort lines of text files in reverse order Example: `sort -r file.txt` (Sort the lines of a file in reverse order) 89. sed 's/foo/bar/g' - Replace all occurrences of a string with another string Example: `sed 's/foo/bar/g' file.txt` (Replace all occurrences of "foo" with "bar" in a file) 90. tail -n +2 - Display all lines of a file except the first line Example: `tail -n +2 file.txt` (Display all lines of a file except the first line) 91. tee - Read from standard input and write to standard output and files Example: `command | tee file.txt` (Execute a command and write its output to a file) 92. df -h -T - Display disk space usage with file system type Example: `df -h -T` (Show disk space usage with file system type) 93. ps aux | grep process_name - Display information about a specific process Example: `ps aux | grep sshd` (Display information about the SSH daemon process) 94. mount -t - Mount a specific file system type Example: `mount -t ext4 /dev/sda1 /mnt` (Mount an ext4 file system to a mount point) 95. df -h - Display disk space usage in a human-readable format Example: `df -h` (Show disk space usage in a human-readable format) 96. tar -xvf - Extract files from a tar archive Example: `tar -xvf archive.tar` (Extract files from a tar archive) 97. tar -tvf - View the contents of a tar archive Example: `tar -tvf archive.tar` (List the files in a tar archive) 98. df -h - Display disk space usage in a human-readable format Example: `df -h` (Show disk space usage in a human-readable format) 99. df -i - Display inode usage Example: `df -i` (Display inode usage) 100. ifconfig -a - Display all network interfaces Example: `ifconfig -a` (Display all network interfaces)