rm command
1) Function: Used to delete a file or directory;
2) -i: ask confirmation before deleting one by one;
3) -f: even if the original file is set to read-only property, also delete, without having to confirm each;
4) -r: The following directory and the files are also removed one by one;
5) Case: delete the test.txt file: rm test.txt; rm -rf bbb recursively delete all the files in the folder bbb