Linux / Unix rm command (remove – delete)
Source: http://www.computerhope.com/unix/urm.htm
About rm
Deletes a file without confirmation (by default).
rm [-f] [-i] [-R] [-r] [filenames | directory]
-f
Remove all files (whether write-protected or not) in a directory without prompting the user. In a write-protected directory, however, files are never removed (whatever their permissions are), but no messages are displayed. If the removal of a write-protected directory is attempted, this option will not suppress an error message.
-i
Interactive. With this option, rm prompts for confirmation before removing any files. It over- rides the -f option and remains in effect even if the standard input is not a terminal.
-R
Same as -r option.
-r
Recursively remove directories and subdirectories in the argument list. The directory will be emptied of files and removed. The user is normally prompted for removal of any write-protected files which the directory contains. The write-protected files are removed without prompting, however, if the -f option is used, or if the standard input is not a terminal and the -i option is not used. Symbolic links that are encountered with this option will not be traversed. If the removal of a non-empty, write-protected directory is attempted, the utility will always fail (even if the -f option is used), resulting in an error message.
filenames
A path of a filename to be removed.
rm myfile.txt
Remove the file myfile.txt without prompting the user.
rm -r directory
Remove a directory, even if files existed in that directory.
Note that if you use rm to remove a file, it is usually possible to recover the contents of that file. If you want more assurance that the contents are truly unrecoverable, consider using shred.