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Note the following:
The following example shows how to enter a multiple line command:
$ COPY/LOG FORMAT.TXT,FIGURE.TXT,ARTWORK.TXT - _$ SAVE.TXT
You can use the DCL command PIPE to create complex command processing statements from a single DCL command. For example, you can execute one or more of the following operations from the same DCL command line:
For more detailed information, see Section 16.29 and the description of
the PIPE command in the OpenVMS DCL Dictionary: N--Z.
3.5 Rules for Entering DCL Commands
The following sections describe specific rules and requirements you
must observe when entering a DCL command.
3.5.1 Case Sensitivity
Use any combination of uppercase and lowercase letters. The DCL
interpreter translates lowercase letters to uppercase. Uppercase and
lowercase characters in parameter and qualifier values are equivalent
unless enclosed in quotation marks (" ").
3.5.2 Required Spaces
You cannot specify null characters (<NUL>) on a DCL command line,
even if you enclose the null character in quotation marks.
3.5.5 Maximum Elements
Include no more than 127 elements (parameters, qualifiers, and qualifier values) in each command line.
Each element in a command must not exceed 255 characters. The entire
command must not exceed 1024 characters after all symbols and lexical
functions are converted to their values. You use symbols, described in
Chapter 14, to pass information to the system in an abbreviated
manner. A lexical function, described in Chapter 17, obtains
information from the system, including information about system
processes, batch and print queues, and user processes, and
then substitutes the result of the operation for itself.
3.5.6 Abbreviating Commands
You can abbreviate a command as long as the abbreviated name remains unique among the defined commands on a system. DCL looks only at the first four characters for uniqueness.
For greater clarity and to ensure that your command procedures are
upwardly compatible, do not abbreviate commands in command procedures.
3.5.7 Example
The following commands are equal:
$ PRIN/COPI=2 FORMAL_ART.TXT $ PRINT/COPIES=2 FORMAL_ART.TXT
Additional rules govern the format of commands when they are used in
command procedures. See Chapter 15 and Chapter 16 for more
information about using commands in command procedures.
3.6 Entering Parameters
File specifications are the most common type of parameter. DCL commands
can accept input file specifications (files that are acted upon by a
command) and output file specifications (files that are created by a
command).
3.6.1 Rules for Specifying Parameters
The following rules apply when specifying parameters in a command line:
DIRECTORY [file-spec]
SHOW PRINTER device-name
$ COPY LISTS.TXT FORMAT.TXT
DELETE file-spec[,...]
$ COPY PLUTO.TXT,SATURN.TXT,EARTH.TXT PLANETS.TXT
There are three types of qualifiers:
The following sections provide information about using and specifying
qualifiers.
3.7.1 Abbreviating Qualifiers
You can abbreviate any qualifier name as long as the abbreviated name
remains unique among all qualifier names for the same command. However,
to ensure that your command procedures are upwardly compatible, do not
abbreviate commands and qualifiers in command procedures.
3.7.2 Default Qualifiers
Commands have default qualifiers; you do not have to specify a
qualifier unless it is different from the command default. The
following sections describe types of qualifiers and qualifier defaults.
The OpenVMS DCL Dictionary contains default information for specific commands.
3.7.3 Command Qualifiers
A command qualifier modifies a command and can appear anywhere in the
command line. However, it is a good practice to place the qualifier
after the command name. If you are specifying multiple qualifiers, you
should place a command qualifier with other command qualifiers that
follow the command name.
3.7.4 Example
In the following example, /QUEUE is a command qualifier. The files SATURN.TXT and EARTH.TXT are queued to the print queue LN03_PRINT:
$ PRINT/QUEUE=LN03_PRINT SATURN.TXT,EARTH.TXT
A positional qualifier can modify commands or parameters and has
different meanings depending on where you place it in the command
string. If you place a positional qualifier after the command but
before the first parameter, it affects the entire command string. If
you place a positional qualifier after a parameter, it affects only
that parameter.
3.7.6 Example
In the following example, the first PRINT command requests two copies of the files SPRING.SUM and FALL.SUM. The second PRINT command requests two copies of the file SPRING.SUM but only one copy of FALL.SUM.
$ PRINT/COPIES=2 SPRING.SUM,FALL.SUM $ PRINT SPRING.SUM/COPIES=2,FALL.SUM
A parameter qualifier can be used only with certain types of
parameters, such as input files and output files. For example, the
BACKUP command accepts several parameter qualifiers that apply only to
input and output file specifications.
3.7.8 Example
In the following example, the /CREATED and /BEFORE qualifiers, which can be specified only with input files, select specific input files for the backup operation. The asterisk (*) is a wildcard character that replaces the file name. BACKUP selects all files with the .TXT file type that were created before December 11, 1996.
$ BACKUP *.TXT/CREATED/BEFORE=11-DEC-1996 NEWFILE.TXT
If you use two or more contradictory qualifiers on a command line, the right-most qualifier overrides the others.
Some commands contain conflicting qualifiers that cannot be specified
in the same command line. If you use incompatible qualifiers, the
command interpreter displays an error message.
3.7.10 Example
Following is an example of conflicting qualifiers. Note that the PRINT command accepts only the /COPIES=2 and the /NOBURST qualifiers because they are the right-most qualifiers in the command line:
$ PRINT MYFILE/COPIES=3/BURST/COPIES=2/NOBURST EARTH.TXT
Qualifiers can accept keywords, file specifications, character strings, and numeric values. When you enter a value for a qualifier, separate the qualifier and the value with either an equal sign (=) or a colon (:).
Some qualifier keywords require additional information. In these cases, separate the keyword from its value with a colon or an equal sign.
To specify multiple keywords that require values, enclose the list in
parentheses and separate the keyword and value with either an equal
sign (=) or a colon (:).
3.7.12 Examples
$ PRINT/COPIES=3 MYFILE.DAT
$ PRINT/COPIES:3 MYFILE.DAT
$ SET SECURITY/PROTECTION:GROUP:RW MYFILE.DAT
$ SET SECURITY/PROTECTION=GROUP=RW MYFILE.DAT
$ SET SECURITY/PROTECTION=(OWNER=RWD,GROUP=RW) myfile.dat
$ SET SECURITY/PROTECTION=(OWNER:RWD,GROUP:RW) myfile.dat
Certain commands and qualifiers (such as the PRINT/AFTER command) accept date and time values. You can specify these values in one of the following formats:
Absolute time is a specific date or time of day. The format for an absolute time is as follows:
[dd-mmm-yyyy][:hh:mm:ss.cc]
The fields are as follows:
| dd | Day of the month: an integer in the range 1 to 31 |
| mmm | Month: JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, or DEC |
| yyyy | Year: an integer |
| hh | Hour: an integer in the range 0 to 23 |
| mm | Minute: an integer in the range 0 to 59 |
| ss | Second: an integer in the range 0 to 59 |
| cc | Hundredths of a second: an integer in the range 0 to 99 |
The following rules apply when specifying absolute time:
You can also specify an absolute time as one of the following keywords:
| TODAY | The current day, month, and year at 00:00:00.0 o'clock |
| TOMORROW | 00:00:00.00 o'clock tomorrow |
| YESTERDAY | 00:00:00.00 o'clock yesterday |
The following table shows examples of absolute time specifications:
| Time Specification | Result |
|---|---|
| 11-DEC-1996:13 | 1 P.M. on December 11, 1996 |
| 11-DEC | Midnight at the beginning of December 11 this year |
| 15:30 | 3:30 P.M. today |
| 19-- | Midnight on the 19th day of the current year and month |
| 19--:30 | 12:30 A.M. on the 19th of this month |
Delta time is an offset (a time interval) from the current date and time to a time in the future. The general format of a delta time is as follows:
"+[dddd-][hh:mm:ss.cc]"
The fields are as follows:
| dddd | Number of days; an integer in the range 0 to 9999 |
| hh | Number of hours; an integer in the range 0 to 23 |
| mm | Number of minutes; an integer in the range 0 to 59 |
| ss | Number of seconds; an integer in the range 0 to 59 |
| cc | Number of hundredths of seconds; an integer in the range 0 to 99 |
If a qualifier is described as a value that can be expressed as an
absolute time, a delta time, or a combination of the two, you must
specify a delta time as if it were part of a combination time. For
example, to specify a delta time value of five minutes from the current
time, use "+:5" (not "0-0:5").
3.8.6 Rules for Specifying Delta Time Format
The following rules apply when specifying delta time:
The following table shows some examples of delta time specifications:
| Time Specification | Result |
|---|---|
| "+3-" | 3 days from now (72 hours) |
| "+3" | 3 hours from now |
| "+:30" | 30 minutes from now |
| "+3-:30" | 3 days and 30 minutes from now |
| "+15:30" | 15 hours and 30 minutes from now |
To combine absolute and delta times, specify an absolute time plus or minus a delta time. Use one of the following formats:
"[absolute time][+delta time]"
[absolute time][-delta time]
The variable fields and default fields for absolute and delta time
values are the same as those described in the preceding sections.
3.8.9 Rules for Specifying Combination Time
The following rules apply when specifying combination time:
The following table shows some examples of combination time specifications:
| Time Specification | Result |
|---|---|
| "+5" | 5 hours from now. |
| "-1" | Current time minus 1 hour. The minus sign (-) indicates a negative offset. (The 1 is interpreted as an hour, not a day, because it is not followed by a hyphen.) |
| "+:5" | 5 minutes from now. |
| "-:5" | Current time minus 5 minutes. |
| "-1-00" | Current time minus 1 day. The minus sign (-) indicates a negative offset. The hyphen (-) separates the day from the time field. |
| "31-DEC:+:5" | 12:05 A.M. on December 31 of the current year. The absolute time specification (before the colon) defaults to midnight on December 31 of the current year. The plus sign (+) indicates a positive offset. |
| 31-DEC:-00:10 | 11:50 P.M. on December 30 of the current year. The absolute time specification (before the colon) defaults to midnight on December 31 of the current year. The minus sign (-) after DEC: indicates a negative offset. |
At the DCL prompt, you can recall previously typed command lines to avoid retyping long command lines. Once a command is displayed, you can reexecute or edit it.
On OpenVMS VAX systems, the recall buffer holds up to 20 previously entered commands.
On OpenVMS Alpha systems, the recall buffer holds up to 254 previously entered commands.
You can display your previously entered commands by using one of the following methods:
Pressing Ctrl/B once recalls the previous command line. Pressing Ctrl/B
again recalls the line before the previous line and so on to the last
saved command line.
3.9.2 Using Arrow Keys
Pressing the up arrow and down arrow keys recalls the previous and
successive command, respectively. Press the arrow keys repeatedly to
move through the commands.
3.9.3 Using the RECALL Command
To examine previously typed command lines, type RECALL/ALL. After reviewing the available commands, you can recall a particular command line by typing RECALL and the number of the desired command.
You can also follow RECALL with the first characters of the command
line you want to display. RECALL scans the previous command lines
(beginning with the most recent one) and returns the first command line
that begins with the characters you typed.
3.9.4 Examples
$ RECALL/ALL
1 SET DEFAULT DISK2:[MARSHALL] 2 EDIT ACCOUNTS.COM 3 PURGE ACCOUNTS.COM 4 DIRECTORY/FULL ACCOUNTS.COM 5 COPY ACCOUNTS.COM [.ACCOUNTS]* 6 SET DEFAULT [.ACCOUNTS]
$ RECALL 4
$ RECALL E
$ EDIT ACCOUNTS.COM
If you are running a utility or an application program that uses
OpenVMS screen management software, you can use Ctrl/B and the up arrow
and down arrow keys to perform command recall; however, line editing
must be enabled. Some utilities that have this feature are Mail,
OpenVMS Debugger, Show Cluster, the System Dump Analyzer (SDA), and the
EVE editor.
3.9.6 Erasing the Recall Buffer
To erase the contents of the recall buffer, enter the RECALL command with the ERASE qualifier. For example:
$ RECALL/ERASE
For security reasons, it is good practice to erase the contents of the
recall buffer after you have entered commands that include passwords.
3.10 Editing the DCL Command Line
At the DCL command level, you can use many individual keys and key
sequences to change what you type. Although different types of
terminals have different operating characteristics, most have standard
function keys and keys that can be used with line editors.
3.10.1 SHOW TERMINAL Command
To see whether line editing is enabled on your terminal, enter the SHOW
TERMINAL command. The current status of line editing is displayed in
the first column under Terminal Characteristics.
3.10.2 Example
In the following example, line editing is not enabled:
$ SHOW TERMINAL Terminal: _VTA130: Device_Type: VT200_Series Owner: ROHBA LAT Server/Port: L121/Port_3 Physical terminal: _LTA130: Input: 9600 LFfill: 0 Width: 80 Parity: None Output: 9600 CRfill: Page: 24 Terminal Characteristics: Interactive Echo Type_ahead No Escape No Hostsync TTsync Lowercase Tab Wrap Scope No Remote No Eightbit Broadcast No Readsync No Form Fulldup No Modem No Local_echo No Autobaud Hangup No Brdcstmbx No DMA No Altypeahd Set_speed No Line Editing Insert editing No Fallback No Dialup No Secure server Disconnect No Pasthru No Syspassword No SIXEL Graphics No Soft Characters No Printer Port Numeric Keypad ANSI_CRT No Regis No Block_mode Advanced_video No Edit_mode DEC_CRT No DEC_CRT2
You can use the SET TERMINAL command to alter the way in which your
terminal edits a DCL command line. By default, changes made with the
SET TERMINAL command apply only to the current session. To set the
terminal each time you log in, you can include SET TERMINAL commands in
your LOGIN.COM file.
3.10.4 Enabling Line Editing
To enable line editing, enter the SET TERMINAL/LINE_EDIT command:
$ SET TERMINAL/LINE_EDIT
You can edit a command line in either insert or overstrike mode. In insert mode, the character you type is inserted to the left of the cursor. In overstrike mode, the character you type overwrites the character indicated by the cursor.
To change editing modes for a single command line, press Ctrl/A (Ctrl/A
acts as a toggle). To change edit modes for your session, enter either
the SET TERMINAL/INSERT or SET TERMINAL/OVERSTRIKE command.
3.10.6 Making Command Lines Wrap
If you use the SET TERMINAL/WRAP command, when you enter more characters than will fit on one line of the terminal screen, the text wraps to the next line.
You can edit only the line where your cursor appears. When text wraps,
you cannot use the up arrow key to move the cursor up to edit the
previous line. To move the cursor up to the previous line, use the
Delete key and delete all the characters in the current line.
3.10.7 Deleting Portions of the Command Line
The Delete key on your keyboard is marked with either the word Rubout, the word Delete, or an X in a left-pointing arrow, depending on the type of terminal you are using. The Delete key back spaces over the most recently entered character and deletes it. On a hardcopy terminal, the deleted letters are displayed between backslash characters so you can see what is being deleted. On a video display terminal, pressing the Delete key erases the character from the screen and moves the cursor backwards.
6489P004.HTM OSSG Documentation 22-NOV-1996 13:16:36.99
Copyright © Digital Equipment Corporation 1996. All Rights Reserved.