(debugging command, practically of no use, you may use SEM(APHORES) instead)

Lists the files which are current processed. There is shown the filename and
the number of the processes, depending on its state:
Rd   read       (process ends in the forseeable future)
LRd  long read  (i.e. process may last any period of time)
Ap   append
LAp  long append
Wr   write
LWr  long write
Op   options (if file is deleted when closed or disconnect)

As write processes exclude each other at multiuser operation, the calling
process will depending on the access time either be suspended or the call
will be rejected.