BRM (Broom) runs in one of two modes:

 	1. Erase all the free space on a mounted disk so that
 deleted files are truly deleted.  It does this by allocating a
 temporary file on the disk and writing a buffer of 0's to each
 block of the file.  The size of the file is made equal to the
 number of free blocks on the volume.  NOTE:  It is strongly
 recommended that BRM be used only on quiescent devices as the
 program allocates every available block on the device!
 	BRM ddn:
 	    where ddn is a mounted Files-11 device.

 	2. Write zeroes to all blocks of an existing file. This
 could be used to erase the contents of a file before it's deleted
 or ensure that a file has known initial contents.
 	BRM ddn:[group,member]filename.ext;ver
 	    where ddn defaults to SY:;
 		  [group,member] defaults to the current UIC;
 		  filename.ext must be specified;
 		  ;ver defaults to the latest version