Format: SHOW FILES

 The SHOW FILES (abbreviated SH FI) command displays the name of the
 input and output files which were specified in the EDT command line.  If
 no output file was specified, then the input file name is also used as
 the output file name.  If /NOOUTPUT or /READ_ONLY was specified in the
 command line, then this will be indicated in place of the output file
 name.