Article 150234 of comp.os.vms:
I accidentally ran across a feature of OpenVMS that I found interesting
enough to share.  This maybe known to many, but since I had never seen
this before, I figured there were others that might be interested in it.
I tried this on OpenVMS 5.5-2/6.1 on VAX and OpenVMS 6.2 on Alpha and it
worked.

What you need to do is create a .COM file with a blank line in it prior to
any real command (non-comment line).  Then at the DCL prompt type a DCL
command followed immediately (no space) by @'com file name'.  It will run
the typed DCL command and then run the com file.  In fact if you put part
of the command in the command file and the first part typed before the '@'
it will do it.  Examples:

*********start of com file*************
$! example com file

$ show default
$ exit
*********end of com file************

> show time@'com file name'
  28-JUN-1996 16:04:22
  AAD01:[USER.WILLIAMS]

*********beginning of com file*******
 time
$ show default
$ exit
*********end of com file**********

> show@'com file name'
  28-JUN-1996 16:05:43
  AAD01:[USER.WILLIAMS]

I believe what is occurring is what is typed prior to the '@' is put into
a type ahead buffer and then when the first line to be parse in the com file
is reached it is appended to the type ahead buffer and then the command is
parsed and acted on.

I know it won't work if you put a space before the '@' and use a blank line.
It gives you an error about too many parameters.  Also if the .COM file has
a command in it prior to a blank line it errors because it tries to append
the $ 'some command' to what was typed.

If you find this interesting and can think of a good use for it, please share.

Arlen Williams
The SABRE Group
arlen_williams@amrcorp.com