When disk space is limited and you are working with large files, you need to clean up after yourself. And human make mistakes. I am not sure if this still does anything in newer rm, but it used to be a common mistake:
$ rm -rf / home/myusername/mylargedir/
(note the extra space after slash)
The real solution is comprised of:
* backups (which are restored periodically to ensure they contain everything)
* proper process which makes accidental removal harder (DCVS & co.)
The real solution is comprised of: