1. 𝐥𝐧(𝐋𝐢𝐧𝐤):
   • Creates hard or symbolic links to files.
   • Usage:
   • Hard link: 𝐥𝐧 [𝐬𝐨𝐮𝐫𝐜𝐞] [𝐥𝐢𝐧𝐤_𝐧𝐚𝐦𝐞]
   • Symbolic link: 𝐥𝐧 -𝐬 [𝐬𝐨𝐮𝐫𝐜𝐞] [𝐥𝐢𝐧𝐤_𝐧𝐚𝐦𝐞]

2. 𝐜𝐚𝐭(𝐂𝐨𝐧𝐜𝐚𝐭𝐞𝐧𝐚𝐭𝐞):
   • Displays the contents of a file.
   • Usage: 𝐜𝐚𝐭 [𝐟𝐢𝐥𝐞]

3. 𝐦𝐨𝐫𝐞 𝐚𝐧𝐝 𝐥𝐞𝐬𝐬:
   • Allows viewing text files one screen at a time.
   • Usage:
   • 𝐦𝐨𝐫𝐞 [𝐟𝐢𝐥𝐞]
   • 𝐥𝐞𝐬𝐬 [𝐟𝐢𝐥𝐞]

4. 𝐡𝐞𝐚𝐝 𝐚𝐧𝐝 𝐭𝐚𝐢𝐥:
   • Displays the beginning or end of a file.
   • Usage:
   • 𝐡𝐞𝐚𝐝 [𝐟𝐢𝐥𝐞]
   • 𝐭𝐚𝐢𝐥 [𝐟𝐢𝐥𝐞]

5. 𝐞𝐜𝐡𝐨:
   • Prints text or variables to the terminal.
   • Usage: 𝐞𝐜𝐡𝐨 [𝐭𝐞𝐱𝐭 𝐨𝐫 𝐯𝐚𝐫𝐢𝐚𝐛𝐥𝐞]

6. 𝐦𝐯(𝐑𝐞𝐧𝐚𝐦𝐞):
   • Can be used to rename files and directories.
   • Usage: 𝐦𝐯 [𝐨𝐥𝐝𝐧𝐚𝐦𝐞][𝐧𝐞𝐰𝐧𝐚𝐦𝐞]

7. 𝐜𝐩(𝐑𝐞𝐜𝐮𝐫𝐬𝐢𝐯𝐞):
   • Copies directories and their contents recursively.
   • Usage: 𝐜𝐩 -𝐫 [𝐬𝐨𝐮𝐫𝐜𝐞] [𝐝𝐞𝐬𝐭𝐢𝐧𝐚𝐭𝐢𝐨𝐧]

8. 𝐟𝐢𝐧𝐝(𝐃𝐞𝐥𝐞𝐭𝐞):
   • Finds files and directories and deletes them.
   • Usage: 𝐟𝐢𝐧𝐝 [𝐝𝐢𝐫𝐞𝐜𝐭𝐨𝐫𝐲] -𝐧𝐚𝐦𝐞 [𝐟𝐢𝐥𝐞𝐧𝐚𝐦𝐞] -𝐞𝐱𝐞𝐜 𝐫𝐦 {} \;

9. 𝐝𝐮(𝐇𝐮𝐦𝐚𝐧 𝐑𝐞𝐚𝐝𝐚𝐛𝐥𝐞):
   • Displays disk usage in a human-readable format.
   • Usage: 𝐝𝐮 -𝐡 [𝐝𝐢𝐫𝐞𝐜𝐭𝐨𝐫𝐲]

10. 𝐝𝐮(𝐒𝐮𝐦𝐦𝐚𝐫𝐢𝐳𝐞):
    • Provides a summary of disk usage of each directory.
    • Usage: 𝐝𝐮 -𝐡 — 𝐦𝐚𝐱-𝐝𝐞𝐩𝐭𝐡=1 [𝐝𝐢𝐫𝐞𝐜𝐭𝐨𝐫𝐲]

11. 𝐭𝐚𝐫(𝐓𝐚𝐩𝐞 𝐀𝐫𝐜𝐡𝐢𝐯𝐞):
    • Creates and manipulates archive files.
    • Usage:
    • Create a tar archive: 𝐭𝐚𝐫 -𝐜𝐯𝐟 [𝐚𝐫𝐜𝐡𝐢𝐯𝐞_𝐧𝐚𝐦𝐞.𝐭𝐚𝐫] [𝐝𝐢𝐫𝐞𝐜𝐭𝐨𝐫𝐲]
    • Extract from a tar archive: 𝐭𝐚𝐫 -𝐱𝐯𝐟 [𝐚𝐫𝐜𝐡𝐢𝐯𝐞_𝐧𝐚𝐦𝐞.𝐭𝐚𝐫]

These commands cover a broad range of tasks, from basic file manipulation to more advanced operations like process management and file compression. Always refer to the manual pages (𝐦𝐚𝐧 [𝐜𝐨𝐦𝐦𝐚𝐧𝐝]) for detailed information about each command and its options.