1. ls: The ls command is used to list the files and directories in a directory. This command can be used with flags to sort the files in a directory by size, date, and other parameters. For example, “ls -l” will show the files in a directory in a long format, including permissions, ownership, and size.
2. cd: The cd command is used to change the current working directory. To navigate to a specific directory, use “cd /path/to/directory”.
3. mkdir: The mkdir command is used to create a new directory. For example, “mkdir new_folder” will create a new directory named “new_folder” in the current directory.
4. rm: The rm command is used to delete files and directories. This command can be used with flags to remove files and directories recursively or to prompt for confirmation before deletion. For example, “rm -r /path/to/directory” will delete the directory and all of its contents.
5. cp: The cp command is used to copy files and directories. For example, “cp /path/to/file /path/to/destination” will copy the file to the specified destination.
6. mv: The mv command is used to move or rename files and directories. For example, “mv /path/to/file /path/to/destination” will move the file to the specified destination, and “mv old_file new_file” will rename the file from “old_file” to “new_file”.
7. pwd: The pwd command is used to display the current working directory.
8. touch: The touch command is used to create new files or update the timestamp of existing files. For example, “touch new_file” will create a new empty file named “new_file”.
9. echo: The echo command is used to display text on the screen. For example, “echo ‘Hello, World!'” will display the text “Hello, World!” on the screen.
10. cat: The cat command is used to display the contents of a file. For example, “cat /path/to/file” will display the contents of the specified file.
11. grep: The grep command is used to search for text in a file or multiple files. For example, “grep ‘text’ /path/to/file” will search for the text “text” in the specified file.
12. find: The find command is used to search for files and directories. For example, “find / -name file.txt” will search for a file named “file.txt” in the entire file system.
13. chmod: The chmod command is used to change the permissions of a file or directory. For example, “chmod 755 /path/to/file” will set the permissions of the file to 755.
14. chown: The chown command is used to change the ownership of a file or directory. For example, “chown user:group /path/to/file” will change the ownership of the file to the specified user and group.
15. ps: The ps command is used to display information about running processes. For example, “ps -ef” will show a detailed list of all running processes.
16. top: The top command is used to display information about the processes that are currently using the most resources. This command can be used to monitor the performance of the system and identify any processes that may be causing issues.
17. kill: The kill command is used to terminate running processes. For example, “kill -9 123” will force kill the process with the PID of 123.
18. sudo: The sudo command is used to execute a command with superuser privileges. For example, “sudo apt-get update” will update the package list as the root user.
19. apt-get: The apt-get command is used to manage packages on Debian-based Linux distributions. This command can be used to install, remove, and update packages on the system.
20. yum: The yum command is used to manage packages on Red Hat-based Linux distributions. This command can be used to install, remove, and update packages on the system.

These are just a few examples of how to use the most popular Linux commands in action. Remember, practice makes perfect and the more you use these commands the more comfortable you will be with the Linux terminal.

In conclusion, Linux commands are the backbone of the Linux operating system and mastering them is crucial for any advanced Linux user. With a deep understanding of the most popular Linux commands and their uses, you’ll be able to perform tasks more efficiently and effectively. Keep practicing and experimenting with different commands and options, and you’ll be a Linux command line pro in no time!