topic Re: Very basic question about Inquire in DCL com files in Operating System - OpenVMS

Very basic question about Inquire in DCL com files

stephenbrayshaw — Mon, 28 Sep 2015 13:34:46 GMT

Hi all,

I am very new to DCL and I have a small command file.

The command file does what I want but once it has finished and I am back at the prompt when I go back up to run the file again I do not see what I expect to.

I have an inquire in the file and when I go back up I see my input for that instead of the previous command I ran.

Example:

The file is called b.com and contains:

$ SAY "Have you ensured that the system was placed into Standalone and then Shutdown?"
$ INQUIRE CONT "Continue? [Y/N]"
$ IF .NOT. CONT THEN EXIT

I run @b and I enter y.

When I go back through the history I get a line with y on it instead of @b how can I stop this from happening?

Re: Very basic question about Inquire in DCL com files

Tom Wetty — Mon, 28 Sep 2015 13:47:36 GMT

Steve:

Your explanation is a bit rough for me to understand you. However, it sounds like you are trying to recall a previous inputted command however, you are seeing only the LAST command you entered. Try entering RECALL/ALL on the command line to see the "@B" command if you desire to enter this command instead of the answer to the inquiry.

Hope this helps. Regards,

Re: Very basic question about Inquire in DCL com files

stephenbrayshaw — Mon, 28 Sep 2015 13:54:22 GMT

Hi Tom,

I am able to see @b at the command prompt but it is that I do not want to see the lines I enter during the execution of the com file when scrolling back up through my history.

Re: Very basic question about Inquire in DCL com files

Tom Wetty — Mon, 28 Sep 2015 13:58:25 GMT

Steve:

There is no way that I am aware of to prevent the storage of inquiry DCL commands in the command buffer.

Re: Very basic question about Inquire in DCL com files

Steven Schweda — Mon, 28 Sep 2015 14:23:23 GMT

> I am very new to DCL [...]

   That may be why you're using INQUIRE. A Web search for. say:
      DCL INQUIRE
should find many explanations of why this is generally a bad idea
(having nothing to do with command-line recall). For a generally
better/safer alternative, see:
      HELP READ /PROMPT

Re: Very basic question about Inquire in DCL com files

MarkOfAus — Mon, 28 Sep 2015 21:34:18 GMT

Following on from Steven:

$ SAY "Have you ensured that the system was placed into Standalone and then Shutdown?"
$ READ/PROMPT= "Continue? [Y/N]" sys$command CONT
$ IF .NOT. CONT THEN EXIT

Re: Very basic question about Inquire in DCL com files

John Gillings — Wed, 30 Sep 2015 00:58:35 GMT

Stephen,

As they say - this is a "feature". Input into the INQUIRE command is considered command input, and so is stored in the command recall buffer. That means if your command procedure has a loop, you can recall previous inputs into subsequent INQUIRE commands. This is intentional.

In contrast, input into the READ command is not stored, so you have a choice as to which behaviour you prefer.

As alluded to by Steven, there are some potential vulnerabilities exposed by INQUIRE. The usual advice is to use READ /PROMPT instead.

Re: Very basic question about Inquire in DCL com files

Hoff — Thu, 01 Oct 2015 15:16:38 GMT

INQUIRE is an ill-documented and potentially dangerous hunk of DCL. INQUIRE allows the user receiving the prompt to execute — yes, execute — certain DCL code. In the prompt. The INQUIRE command is best left to very advanced DCL users, and — unless they're intentionally inserting a subtle backdoor — even they will generally avoid this command. Due to the risks of this command, INQUIRE is explicitly prohibited in certain DCL procedure run-time contexts. IMNSHO, INQUIRE should have been deprecated decades ago. Use READ /PROMPT, as mentioned above.