HP 3000 Manuals HP 3000 Manuals
Modifying the User Interface (Command Interpreter)
The Command Interpreter (CI) provides and controls the user interface to
MPE XL. It is the means by which commands are entered to the system, and
it regulates many aspects of the system environment. The following
material describes several ways in which the user interface can be
modified by modifying the CI.
Customizing the Logon
There are three ways to tailor the logon: in the SYSGEN utility; in the
WELCOME message; and with User Defined Commands (UDCs).
Use the SYSGEN utility to change the system and CI prompts. Refer to
Localizing and Customizing System Information (32650-90046) for further
details.
The WELCOME message is the first screen display a user sees after logging
on. The message can be easily changed using the :WELCOME command. The
command can be issued only from the Console unless distributed to other
users with the :ALLOW command.
The WELCOME message is usually stored in an ASCII format file. To
activate the message, enter
:WELCOME filename
To create a message interactively, use :WELCOME with no parameters. You
will then be prompted with a "#" to begin the first line of the message.
The message terminates and the command ends when a Return is entered in
response to the "#" prompt.
Changing the Prompt
The CI prompt value is stored in a predefined MPE XL variable called
HPPROMPT. At logon, HPPROMPT is initialized as ":", unless changed using
the SYSGEN utility. To temporarily change the prompt, use the :SETVAR
command to assign a new value to HPPROMPT. For example,
:SETVAR HPPROMPT ">"
>
Changing the Search Path for Command/Program Files
System files are searched in the following order: UDCs, MPE XL commands,
and Command Files and program files. The CI is capable of searching for
the command or program file name through specified groups, that is, of
following a search path. The value of the search path is stored within
the predefined variable HPPATH. The default value of HPPATH is
!HPGROUP,PUB,PUB.SYS.
The user can control the process of Command File and program file
searching by redefining the HPPATH variable. For example, if the user
has command and program files in the home group, and the user is logged
on to another group, the default search path will fail to find the files.
By resetting the search path to include the home group, the proper files
will be found. In this example, this could be accomplished with the
following command:
:SETVAR HPPATH HPPATH + ",!HPHGROUP"
The advantage of setting the search path to encompass the group(s)
containing your Command Files or program files is that if the filename by
itself is entered, it will automatically be executed without the need to
qualify or explicitly enter the :RUN command. This not only relieves
the user of having to enter the group and account names, it allows the
entry to appear as though it is a customized command.
If the user has a command or program file with the same file name as a
UDC or a MPE XL command, that file can only be executed by using the :XEQ
command.
Changing the Terminal Timeout Interval
The predefined HPTIMEOUT variable determines the number of minutes the CI
will wait for new terminal input before terminating a session. The
default value is zero, which is interpreted as no timeout. The user may
alter the value to a positive number between 1 and 546 by using the
:SETVAR command. For example,
:SETVAR HPTIMEOUT 60
will terminate a session if the user does not enter a command over a
period of 60 minutes.
Reissuing Commands
As you make entries at the prompt, the CI can save each entry to the
command line history stack. The predefined variable, HPREDOSIZE, is used
to control the number of previous entries that are retained by the
system. The default value of HPREDOSIZE is 20. Use the :SETVAR command
to change the default to any number between 0 and 1000.
The effect of using the history stack is that once a command is entered
during a session, it need not be entered again. To reissue a command,
use :DO or :REDO. The contents of the stack may be viewed by entering the
:LISTREDO command.
Changing Other Predefined Variables
MPE XL initializes the values of certain predefined session variables
upon logon. These variables include the predefined variables beginning
with the letters "HP" and the two system Job Control Words, JCW and
CIERROR These variables and their values may be diplayed by entering
:SHOWVAR @
To assign a new value to a predefined variable, use the :SETVAR command.
To do the same from within a program, use the intrinsic HPCIPUTVAR, or
access :SETVAR from the COMMAND or HPCICOMMAND intrinsics.
Creating User Defined Variables
In addition to the predefined system variables, MPE XL lets the user
create individualized session/job specific variables. MPE XL
user-defined variables, as with predefined variables, can be defined as
integers, Booleans, or strings (surrounded by quotes). These variables
are set using the same commands and intrinsics used to modify the
predefined READ/WRITE variables.
Command Interpreter Programming Features
Because the CI provides a "programming environment", MPE XL variables
commands can be used to write customizing programs at the system level.
The programmatic and command options include
* Predefined and user defined variables.
* Expression evaluation (including FINFO and expression
substitution).
* The :IF command for branching.
* The :WHILE command for looping.
* The :CALC command for expression evaluation.
* The :INPUT command for interactive assignment to variables.
* The :SETVAR, :SHOWVAR, and :DELETEVAR commands to manipulate
variables.
* The :ECHO command for displaying a message.
* The :PRINT command for general purpose file copying.
* The :COPY command for fast disk file copying.