rm
rm [-r] <name>
Risk: Can lose work
What it does
Deletes files for good. There is no bin and no undo.
When to use it
Only after ls shows exactly what you will delete.
Example
$ rm a.tmp b.tmpDelete two temp files.
$ rm -r oldDelete a folder and everything inside it.
$ rmdir oldDelete a folder only if it is empty.
Learn it in: Delete with care: rm has no undo · Official docs