PARSEC Technical Information

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===== VMS and DCL HELP =====

"HELP is your friend."  We say that often to new students here at PARSEC VMS classes.

The DCL HELP facility and command have long been recognized as essential, both for the novice user and the experienced VMS guru alike. Bespoken help libraries are available not only to cover the essential DCL commands themselves, but also for specific utility programs such as (VMS) MAIL and PHONE, and for system administration tools such as SYSGEN, SYSMAN, TCPIP, AUTHORIZE and more.  For these latter, a built-in utility ''HELP'' command gives access to that utility's command help-text.  For example:

<code>
$ MCR AUTHORIZE
UAF> HELP
     ...
</code>

**For general DCL use**, the ''HELP'' command is essential -- For example, try (in your logged-in VMS session):

<code>
$ HELP                ! access to the whole DCL HELP facility, including an overview of topics

$ HELP HELP           ! getting started with HELP

$ HELP INSTRUCTIONS   ! how to use HELP (details)

$ HELP HINTS          ! useful tips on getting the most out of HELP topics
</code>

Of course, to get help on a specific DCL command, for instance on the ''COPY'' command, use:

<code>
$ HELP COPY
</code>

Within HELP's overview of topics, any topic which appears in all ''UPPERCASE'' is a DCL command verb; topics in Mixed/lower case are concept topics, such as ''Filespec'' and ''Errors'' (both of which you should review).

The essential DCL file management commands include ''COPY'', ''CREATE'', ''DELETE'', ''DIRECTORY'', ''RENAME'', ''PURGE'' and ''SET FILE'' -- you can look up each of these in the HELP facility (see example above).

Other very handy commands include ''PIPE'', ''READ'', ''RECALL'', ''SEARCH'', ''TYPE'' and ''WRITE''.

Also, look at the HELP entries for ''Filespec'', ''Line_editing'', (file) ''Protection'', ''Security'', ''Integer'', ''String'' and ''Expression''.

If you are a software developer/programmer, see the HELP entries for ''BASIC'', ''CC''/''CXX'', ''COBOL'', ''FORTRAN'', ''PASCAL'', ''LINK'', ''DEBUG'' and ''RUN''.  And both programmers and sysadmins should see ''EDIT'' and ''LSEDIT'' for details about text editing.  These lists of commands are not comprehensive -- there's lots more to explore, depending on your needs.

Both programmers and sysadmins often need to look up the details of the so-called "DCL Lexical Functions", but if you want help on, say, the F$CVTIME function, this won't work:

<code>
$ HELP F$CVTIME
Sorry, no documentation on F$CVTIME
</code>

Instead, you'll have to remember that all of these lexical functions are sub-topics under HELP's ''Lexicals'' topic, so use:

<code>
$ HELP LEXICAL F$CVTIME
  ...
</code>

(you could abbreviate ''LEXICAL'' to just ''LEX'').  Also, see the wiki article [[DCL Lexical Functions]] for much more information about DCL lexicals.

A special function of DCL HELP is the [[dcl_error_messages|HELP /MESSAGE]] command, which you should become familiar with to solve specific command syntax and operational problems.