topic Re: Does the Pipe command work on all versions and platforms? in Operating System - OpenVMS

Does the Pipe command work on all versions and platforms?

Vineet Deshpande — Thu, 02 Oct 2008 10:01:56 GMT

Hi,

I wanted to know if the PIPE command works on all platforms and versions of OpenVMS?

Are there any versions where Pipe doesn't work? Basically I am interested in sequential command execution. Is there any documentation which will tell me if PIPE works on some platforms and not on others?

The reason for this is that in my code I have used it to run commands and wanted to know if it will work on all the platforms and versions.

Please help.

Thanks,

Vineet

Re: Does the Pipe command work on all versions and platforms?

Steven Schweda — Thu, 02 Oct 2008 10:42:10 GMT

No. A Google search for:
vms OR openvms pipe "new features"
found, among other things:

http://pupgg.princeton.edu/cdrom12/html/ssb71/6480/6480p.htm

2.1.1 PIPE Command

OpenVMS Version 7.1 introduces some popular UNIX command shell processing functions. [...]

> Please help.

Please try harder.

Re: Does the Pipe command work on all versions and platforms?

Hein van den Heuvel — Thu, 02 Oct 2008 10:42:21 GMT

The PIPE command was introduced for OpenVMS V7.1

It is available and believed to work on that and later version. VAX, Alpha and I64.

>> Basically I am interested in sequential command execution.

Please explain what that means.

TO me sequential execution means execute 1, then execute 2 and so on. A basic command file will do thsi for individual commands and a batch queue (with job-limits or SYNC commands) can be used to sequentially execute larger 'jobs'.

>> The reason for this is that in my code I have used it to run commands and wanted to know if it will work on all the platforms and versions.

It should. Do yo have any reason to doubt? Then please elaborate with concrete commands and (error) messages which perhaps prompted the question.

hth,
Hein.

Re: Does the Pipe command work on all versions and platforms?

Vineet Deshpande — Thu, 02 Oct 2008 11:07:31 GMT

Basically the command I am running is:-

PIPE write sys$output "" ; ; write sys$output ""

I am interested in parsing the output of and hence require the delimiter strings.

Right now I haven't faced any problems with the PIPE command but that maybe because the versions on which I have tested are above v7.0.

I want to know whether I will have problems if I execute this command on an earlier version of OpenVMS.

Thanks,

Vineet

Re: Does the Pipe command work on all versions and platforms?

Steven Schweda — Thu, 02 Oct 2008 11:22:32 GMT

> I want to know whether I will have problems
> if I execute this command on an earlier
> version of OpenVMS.

Well, duh. It was a NEW FEATURE in V7.1. Do
you think it will work in older versions? (I
don't.)

What would be different if you did this
instead?:

write sys$output ""

write sys$output ""

I see no compelling reason to use PIPE here.

Re: Does the Pipe command work on all versions and platforms?

Steven Schweda — Thu, 02 Oct 2008 11:26:00 GMT

Which part of "No" wasn't clear?

Re: Does the Pipe command work on all versions and platforms?

labadie_1 — Thu, 02 Oct 2008 11:53:08 GMT

>>>I want to know whether I will have problems if I execute this command on an earlier version of OpenVMS.

I guess you will have the same error message I get when I type something which is not a Vms command defined in sys$common:[syslib]dcltables.exe, example

$ uiuiuiui
%DCL-W-IVVERB, unrecognized command verb - check validity and spelling
\UIUIUIUI\

You should get VERB from
http://vms.tuwien.ac.at/freeware/VERB/

and "play" with it.

Re: Does the Pipe command work on all versions and platforms?

Vineet Deshpande — Thu, 02 Oct 2008 12:32:55 GMT

Hi,

I did try the method:-

write sys$output
command
write sys$output

but was having some problems which were solved by the Pipe command. But I guess if I want to implement a more generic approach I will have to revert back to the old method.

Anyways thanks to all for your answers.

- Vineet

Re: Does the Pipe command work on all versions and platforms?

Hoff — Thu, 02 Oct 2008 12:56:08 GMT

I'm going to make a number of assumptions and guesses around what application requirement you are intending to solve here.

The usual approaches are:

$ cmd/OUTPUT
$ @mumble /OUTPUT
$ CALL /OUTPUT
$ @TT: /OUTPUT
$ SUBMIT (with or without EXECSYMB)

Applications can also internally contain tools for logging or redirection, or can be extended to contain these capabilities.

And then (and least desirably) you get to I/O redirection using SYS$OUTOUT: or related; /USER is better than not.

$ DEFINE /USER
$ DEFINE

where I/O redirection tends not to work as someone familiar with pipes might expect or might want.

I'd suggest reading the Writing Real Programs in DCL book (2nd ed) book Paul and I wrote a while back, though that's out of print.

Re: Does the Pipe command work on all versions and platforms?

Steven Schweda — Thu, 02 Oct 2008 14:21:31 GMT

> I did try the method:-
> [...]
> but was having some problems [...]

My psychic powers are too weak to tell me
what "command" was, or what "some problems"
were, so it's hard to say if PIPE was the
best way to solve them. If you'd like some
actual advice, provide some actual
information.

Re: Does the Pipe command work on all versions and platforms?

Hoff — Thu, 02 Oct 2008 14:36:25 GMT

Based on recent postings, the goal here appears to be to build and to present a management interface. The approach used appears to be willing to use unsupported (and subject to change) means (parsing DCL command output) to generate the necessary data for the UI.

I'm somewhat surprised that DCL itself is used here; I'd tend to expect either a dedicated probe application image or the use of SNMP. (Or both.)

One other thing I forgot to mention over in that other UI (workstation versus server icon) thread: these system management tools are a gigantic and very juicy security target for hackers.