mkdir <name>: Creates a new directory. touch <filename>: Creates an empty file or updates timestamp. cp <source> <destination>: Copies files or directories. mv <source> <destination>: Moves or renames files or directories. rm <file>: Removes a file. rmdir <directory>: Removes an empty directory. rm -r <directory>: Removes a directory and its contents recursively. Use with extreme caution! This command doesn't ask twice and has been known to eat homework, projects, and even dreams.