Disk Utility Wedge by Jim Klitzing is a multi-fuction utility for the Commodore 64.  There are full docs on the disk.  Here's an excerpt from the docs:

I wrote this program with several objectives in mind.... I wanted to be able to access a lot of utility programs without having to load them in every  time I wanted to use one. Also, I did not want it to slow down the running of  programs, change any of the standard basic commands, nor use up any of the  basic memory space. I also wanted to be able to use abbreviated DOS commands.

 The wedge resides in memory from hex $a001 to $cfff. Any program that does not use memory in this range should be able to co-exist. When Micromon is in  use, the casette buffer is also used. About 2/3 of the memory used by the
 wedge is under the basic rom. Since the wedge is all machine language, basic  is not needed to perform any of the wedge commands, and is switched out  (temporarily) while they are being performed. All wedge commands must be
 preceeded by an asterisk (*). The asterisk tells basic (direct mode only) that  the command that follows should be turned over to the wedge interpreter.

A newer version of this program can be found HERE.