Polluks: Category

2022-06-24T18:46:57Z

Jane.doe: Created page with "'''SYS$INPUT''' is a process-permanent logical name that denotes the default file or device from which DCL reads input. =Default= In an int..."

2019-11-28T15:45:56Z

Created page with "'''SYS$INPUT''' is a process-permanent logical name that denotes the default file or device from which DCL reads input. =Default= In an int..."

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'''SYS$INPUT''' is a [[Process-Permanent Logical Name|process-permanent logical name]] that denotes the default file or device from which DCL reads input.

=Default=
In an interactive process, the default value of SYS$INPUT is the terminal.
In a command procedure run interactively, the default value of SYS$INPUT is the command procedure file.
In a command procedure run as a [[Batch Job|batch job]], the default value of SYS$INPUT is the command procedure file.

=Usage=
If you specify SYS$INPUT as the file specification for a command, you are prompted for the text while still remaining at the DCL level. For example:
<nowiki>
$ mail sys$input jdoe
Enter your message below. Press CTRL/Z when complete, or CTRL/C to quit:
hi there
Exit
New mail from JDOE
$
</nowiki>

You can also redefine SYS$INPUT so that an [[Image|image]], invoked by a [[Command Procedure|command procedure]], reads input from the terminal or another file. Because [[DCL]] always obtains input from the default input stream, DCL ignores a redefinition of SYS$INPUT. The OpenVMS Help Facility offers the following example of an input file for the [[SORT]] command:
<nowiki>
! PEOPLE.DAT
! A set of data with embedded key qualifiers for the SORT command.
!
! Usage: SORT@PEOPLE.DAT
!
/KEY=(POS:10,SIZE:10) sys$input people.out
Fred Flintstone 555-1234
Barney Rubble 555-2244
Wilma Flintstone 555-1234
Betty Rubble 555-2244
George Slate 555-8911
Dino Dinosaur 555-1234
</nowiki>

Calling SORT@PEOPLE.DAT would therefore produce PEOPLE.OUT that would contain the table above sorted by surname.

=Displaying=
The current value of SYS$INPUT can be displayed with the [[SHOW LOGICAL]] command. It displays only the device portion of the string. In the example below, SYS$INPUT is defined to a file:

"SYS$INPUT" = "_DSA0:" (LNM$PROCESS_TABLE)

In the example below, SYS$INPUT is defined to a terminal:

"SYS$INPUT" = "_TNA18:" (LNM$PROCESS_TABLE)

=Redefining=
SYS$INPUT can be redefined so that an image takes its input from wherever it is redefined to. Most commands, except for those [[CLI#Commands Executed Inside the CLI|executed inside DCL]], invoke images. Because DCL always obtains input from the default input stream, DCL ignores a redefinition of SYS$INPUT. In the following example, SYS$INPUT is redefined to SYS$COMMAND (the terminal) so that the image invoked with the next command ([[EVE|TPU]]) would use the terminal and not the command procedure file as a source of input.
<nowiki>
$ DEFINE/USER_MODE SYS$INPUT SYS$COMMAND
$ EDIT/TPU MYFILE.DAT
.
.
.
</nowiki>
When the image is finished, SYS$INPUT resumes with the default input stream (the command file).

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	When the image is finished, SYS$INPUT resumes with the default input stream (the command file).		When the image is finished, SYS$INPUT resumes with the default input stream (the command file).

			[[Category:Logical Name]]

SYS$INPUT - Revision history

Polluks: Category

Jane.doe: Created page with "'''SYS$INPUT''' is a process-permanent logical name that denotes the default file or device from which DCL reads input. =Default= In an int..."