OpenVMS User's Manual

In contrast, the Backspace key (or the left arrow key) back spaces over characters but does not delete them.

If line editing is enabled, you can use Ctrl/U to delete characters from the beginning of the line to the current cursor position. If line editing is not enabled, you can use Ctrl/U to cancel an entire line. The system ignores the line and redisplays the DCL prompt.

3.11 Defining Terminal Keys

A key definition is a string of characters that you assign to a particular terminal key. When a key is defined, you can press it instead of typing the string of characters. A key definition usually contains all or part of a command line. Using key definitions, you can customize your keyboard so that you can enter DCL commands with fewer keystrokes. When you press a defined key, the system either displays the command on your terminal or executes the command, depending on whether the command was defined using the /TERMINATE qualifier.

3.11.1 Definable Keys

Some definable keys are automatically enabled for definition (for example, keys PF1 to PF4 and keys F17 to F20 on LK201 keyboards). However, before you can define other keys, including KP0 (keypad 0) to KP9 and the keypad keys period, comma, minus, and Enter, you must enable them for definition by entering either the SET TERMINAL/APPLICATION_KEYPAD or the SET TERMINAL/NONUMERIC command.

3.12 Summary of Key Sequences

The following sections describe keys and key sequences that you can use to perform specific operations.

3.12.1 Keys That Enter DCL Commands

The following keys enter DCL commands:

• Ctrl/Z and F10
  Signals the end of the file for data entered from the terminal. Ctrl/Z displays as Exit. This key is available only on an LK201 keyboard.
• Return
  Sends the current line to the system for processing. On some terminals, the Return key is labeled CR. If you are not already logged in, Return initiates a login sequence.

The following keys interrupt DCL commands:

• Ctrl/C and F6
  During command entry, cancels command processing. Ctrl/C displays as Cancel. This key is available only on an LK201 keyboard.
• Ctrl/T
  Momentarily interrupts terminal output to display a line of statistical information about the current process. This display includes your node and user name, the time, the name of the image you are running, and information about system resources used during your current terminal session.
  You can also use Ctrl/T to determine whether the system is operating. Ctrl/T does not return information if the system is temporarily unresponsive or if your terminal is set to NOBROADCAST. To use Ctrl/T, you must first enter the SET CONTROL=T command (in the system login command procedure, in your personal login command procedure, or interactively).
• Ctrl/Y
  Interrupts command processing. Ctrl/Y displays as Interrupt. You can disable Ctrl/Y with the command SET NOCONTROL=Y.
  Under most conditions, Ctrl/Y returns you to the DCL prompt. The program running is still active. You can enter any built-in command then continue the program with the CONTINUE command. (Press Ctrl/W to refresh the screen after you enter the CONTINUE command.)

The following keys recall commands:

• Ctrl/B or up arrow
  Recalls up to 20 (VAX) or 254 (Alpha) previously entered commands.
• Down arrow
  Displays the next line in the recall buffer.

The following keys control cursor position:

• <X|, Delete
  Deletes the last character entered at the terminal. On some terminals, the Delete key is labeled RUBOUT. The Delete key also works when line editing is disabled.
• Ctrl/A and F14
  Switches between overstrike and insert mode. The default mode (as set with the SET TERMINAL/LINE_EDITING command) is reset at the beginning of each line. This key is available only on an LK201 keyboard.
• Ctrl/D and left arrow
  Moves the cursor one character to the left.
• Ctrl/E
  Moves the cursor to the end of the line.

• Ctrl/F and right arrow
  Moves the cursor one character to the right.
• Ctrl/H, Backspace, and F12
  Moves the cursor to the beginning of the line. This key is available only on an LK201 keyboard.
• Ctrl/I and Tab
  Moves the cursor to the next tab stop on the terminal. The system provides tab stops at every eighth character position on a line. Tab settings are hardware terminal characteristics that, in general, you can modify. The Tab key also works when line editing is disabled.
• Ctrl/J, Linefeed, and F13
  Deletes the word to the left of the cursor. This key is available only on an LK201 keyboard.
• Ctrl/K
  Advances the current line to the next vertical tab stop.
• Ctrl/L
  Causes the cursor to go to the beginning of the next page. This use of Ctrl/L is ignored when line editing is enabled.
• Ctrl/R
  Repeats the current command line and leaves the cursor positioned where it was when you pressed Ctrl/R.
• Ctrl/U
  Deletes all text in the current input line that is to the left of the cursor.
• Ctrl/V
  Turns off some of the line editing function keys. For example, if you press Ctrl/V followed by Ctrl/D, a Ctrl/D is generated instead of the cursor moving left one character. Ctrl/D is a line terminator at DCL level.
  When combined with Ctrl/V, characters that are not line terminators have no effect. Examples are Ctrl/H and Ctrl/J. However, certain control keys, such as Ctrl/U, retain their line editing functions.
• Ctrl/X
  Cancels the current line and deletes data in the type-ahead buffer.
• F7, F8, F9, F11
  Reserved by Digital.

The following keys control screen display:

• Ctrl/O
  Alternately suspends and continues display of output to the terminal. Ctrl/O displays as Output off and Output on.
• Ctrl/S
  Suspends terminal output until Ctrl/Q is pressed.

• Ctrl/Q
  Resumes terminal output suspended by Ctrl/S.
• Hold Screen and No Scroll
  Suspends terminal output until the key is pressed again. The Hold Screen key is available only on an LK201 keyboard, and the No Scroll key is available only on a VT100 keyboard.

This chapter describes how to create and manipulate files locally, and over a DECnet for OpenVMS network. This chapter includes information on:

• Understanding file names and file specifications
• Using wildcards with file names
• Other file names
• Creating and modifying files
• Displaying the contents of files
• Deleting files
• Protecting files from other users
• Printing files

For additional information, also see the following:

• OpenVMS DCL Dictionary and in online help, for commands discussed in this chapter
• OpenVMS System Manager's Manual, for information about accessing remote nodes
• DECnet for OpenVMS Networking Manual, for information about networks

A file is a unit that the OpenVMS operating system uses to store human-readable and machine-readable data. When you create or name a file, you must specify certain information so that the system can locate and identify the file. You do not have to include all the elements of a complete file specification (see Section 4.2.1). However, you must include a file name or file type to identify it to both the system and you. For example, PAYROLL_MEMO.TXT is a valid file specification. PAYROLL_MEMO is the file name, and .TXT is the file type.

4.2.1 Providing a Complete File Specification

To override system defaults or to perform file operations over a network, you must provide a complete file specification. A complete file specification has the following format:

node::device:[directory]filename.filetype;version 

The elements are as follows:

Node	A network node name; applicable only to systems that support DECnet for OpenVMS. Does not apply to files stored on magnetic tape.
Device	The name of the physical device on which the file is stored or is to be written. For information on accessing files stored on physical devices, see Section 12.7.
Directory	The name of the directory under which the file is cataloged. Square brackets ([]) or angle brackets (<>) can be used to delimit directory names. Does not apply to files stored on magnetic tape.
Filename	The name of the file. It can have up to 39 alphanumeric characters, including the hyphen and the underscore.
Filetype	Identification of the structure or the type of data in the file. The file type can have up to 39 alphanumeric characters, including the hyphen and the underscore.
Version	The version number of the file. Versions are identified by a decimal number, which is incremented by 1 each time a new version of the file is created. The system automatically assigns a version number unless you specify one.

4.2.2 Rules for File Specifications

Use the following rules to specify the elements of a file specification:

• Give the file a name that is meaningful to you. The file name can be up to 39 characters chosen from the letters A to Z (uppercase or lowercase), the numbers 0 to 9, underscores (_), hyphens (-), and dollar signs ($).
• Do not use a hyphen as the first or last character in the file name. While it is possible under some conditions to successfully create a file with the hyphen as the first character in the file name, special handling is required to access this file.
• Include 0 to 39 characters in a file type.
• Precede a file type by a period.
• Precede version numbers with a semicolon or a period. (When the system displays file specifications, it displays a semicolon in front of the file version number.)
• Do not use a directory field to refer to files on magnetic tape (directories apply only to files on disks).
• Include a node name only if your system is part of a network.
• When naming files on mass storage devices (such as disks and magnetic tapes), include the fields for file name, type, and version.

With certain commands, if you omit the file type, the system applies a default value. The following table lists some of the more common default file types used by DCL commands:

File Type	Contents
.CLD	Command description file
.COM	Command procedure file
.DAT	Data file
.DIF	Output file created by the DIFFERENCES command
.DIR	Directory file
.DIS	Distribution list file for the Mail utility
.EDT	Startup command file for the EDT editor
.EXE	Executable program image file created by the linker
.HLB	Help text library file
.HLP	Input source file for help libraries
.INI	Initialization file
.JOU	Journal file created by the EDT editor
.LIS	Listing file created by a language compiler or assembler; default input file for the PRINT and TYPE commands
.LOG	Batch job output file
.MAI	Mail message file
.MEM	Output file created by DIGITAL Standard Runoff (DSR)
.PS	POSTSCRIPT format file
.REGIS	Regis format file
.RNO	Input source file for DIGITAL Standard Runoff (DSR)
.SIX	Sixel graphic file
.SYS	System image file
.TJL	Journal file created by the DECTPU and ACL editors
.TLB	Text library file
.TMP	Temporary file
.TPU	Command file for the EVE editor
.TPU$JOURNAL	Journal file created by the EVE editor
.TXT	Input file for text libraries or Mail utility output files

4.2.4 Default File Types for Language Source Programs

The following table lists the default file types for some high-level language source programs:

File Type	Contents
.ADA	Input source file for the DEC Ada compiler
.BAS	Input source file for the BASIC compiler
.B32	Input source file for the VAX BLISS-32 compiler
.C	Input source file for the DEC C compiler
.COB	Input source file for the VAX COBOL compiler on OpenVMS VAX systems and the DEC COBOL compiler on OpenVMS Alpha systems
.FOR	Input source file for DEC Fortran (DEC Fortran for OpenVMS VAX systems was formerly VAX Fortran)
.M64	Input source file for the MACRO-64 assembler for OpenVMS Alpha
.MAP	Memory allocation map created by the Linker utility
.MAR	Input source file for the VAX MACRO assembler or the MACRO-32 Compiler for OpenVMS Alpha
.MLB	Macro library for the MACRO assembler
.MSG	Source file that specifies the text of messages
.OBJ	Object file created by a language compiler or assembler
.OLB	Object module library
.OPT	Options file for input to the LINK command
.PAS	Input source file for the Pascal compiler
.PLI	Input source file for the PL/I compiler
.STB	Symbol table file created by the Linker utility
.UPD	Update file of changes for a VAX MACRO source program; also input to the SUMSLP utility

4.2.5 File Versions

In addition to a file name and file type, every file has a version number. Version numbers are decimal numbers from 1 to 32,767 that differentiate versions of a file. When you create a file, the system assigns it the version number 1.

You can have several versions of the same file. Unless you specify a version number, the system uses the highest existing version number of that file. If you specify the version number 0, the system uses the highest existing version. When you modify a file with a command, application, or text editor (such as EVE) that creates a new version of the file, the file name remains the same but the version number is incremented by one.

Precede version numbers with a semicolon or a period. When the system displays file specifications, it displays a semicolon in front of the file version number.

4.2.6 Specifying File Versions

You can refer to versions of a file in a relative manner by specifying a zero or a negative version number. Specifying zero locates the latest (highest numbered) version of the file. Specifying -1 locates the next-most-recent version, -2 the version before that, and so on. To locate the earliest (lowest numbered) version of a file, specify -0 as the version number. Note that you cannot create files with a version number higher than 32767. If you attempt to create a new file with a version number higher than 32767, you will receive an error message.

4.2.7 Controlling the Number of File Versions

The /VERSION_LIMIT qualifier for the CREATE/DIRECTORY, SET DIRECTORY, and SET FILE commands lets you control the number of versions of a file. If you exceed the version limit, the system automatically purges the lowest version file in excess of the limit. For example, if the version limit is 5 and you create the sixth version of a file (ACCOUNTS.DAT;6), the system deletes the first version of the file (ACCOUNTS.DAT;1). To view the version limit on a file, enter the DIRECTORY/FULL command. The version limit is listed in the File attributes: field.

4.2.8 Network Node Names

A node is an individual computing system that is part of a computer network. If your system is part of a network, the node that you access when you log in is your local node. Other nodes in the network are remote nodes. Use a node name when you want to specify a file on a remote node.

4.2.9 Node Specification Format and Rules

A node specification has the following format:

node["access-control-string"]:: 

Observe the following rules when entering a node name as part of a file specification:

• Node names can contain 1 to 6 alphanumeric characters and must contain at least one alphabetic character. For example:
  • AFTP1
  • F2OTR2
  • MYNODE
• A node name (with or without an access control string) must always be followed by a double colon (::).
• When you specify a node name, you can include a 0- to 42-character access control string. An access control string contains login information to be sent to the remote node. For more information on access control strings, see Section 4.2.21.
  Note that the required double colon follows the access control string.
• You can use a logical name in place of the node name. For information on logical node names, see Chapter 13.

On OpenVMS systems, you can specify node full names. However, you must have DECnet--Plus software installed for full node names to be recognized.

Valid full node names can contain up to 255 characters and can include any characters except the following:

• Spaces
• Tabs
• The characters: comma (,), quotation marks (" "), slash (/), exclamation point (!), equal sign (=), plus sign (+), at sign (@), apostrophe ('), parentheses (( )), and double colons (::)
• A single colon (:) as the first or last character

If a full node name is enclosed in quotation marks (" "), it can contain any characters except unmatched quotation marks. Note that if there are quotation marks within the node name, the quotation marks must be doubled and the entire string, including the quotation marks, must also be enclosed in quotation marks.

Although the OpenVMS software enforces few rules on the syntax of node names, the actual set of valid node names is constrained by the DECnet software running on your system. For further information on full names, refer to the DECnet--Plus documentation. The syntax rules, including valid character codes, are described in detail in the DECnet--Plus DECdns Management Guide.

4.2.11 Examples

In the following example, the entire string is in quotation marks because there are quotation marks in the node name:

"MARY:.UNIVERSITY.""SCIENCE LAB""" 

Other examples of valid full node names are:

• MYNODE
• MASSACHUSETTS:.BUSINESS.YOURNODE
• A.B;C

When you access a file on a remote node, DECnet logs in at the remote node. To do this, the system needs login information for that node. You can supply the system with an access control string. If you omit the access control string, the login information sent to the remote node is determined as follows:

• If a proxy login account exists for you on the remote node, then the system logs you in using that account. A proxy login account allows selected users to log in to a node.
• If a proxy login account does not exist, the system uses the default DECnet account for that node as specified by the local system manager.

If you include an access control string, the system uses it to log you in to the remote node. The remainder of the file specification is passed to the remote node and is interpreted there.

If you specify a local node as part of a file specification, the system logs you in over the network to perform the file operation, even though the file exists on your local node. For information about additional ways to access remote systems, see the OpenVMS System Manager's Manual.

4.2.13 Note: Examples in This Chapter

Throughout the remainder of this chapter, examples that specify a node name do not always include an access control string. This is because proxy accounts enable users to perform operations on the remote systems in these examples.

4.2.14 Using Network File Specifications

There are three formats for network file specifications:

• Conventional
• Foreign
• Task

In each format, the node specification can include an access control string. For more information, see the DECnet for OpenVMS Networking Manual.

4.2.15 File Name Format

The conventional format for files is:

node::device:[directory]filename.type;version 

A foreign file specification is a file that does not conform to OpenVMS syntax. The format used to provide a foreign file specification is:

node::"foreign-file-spec-string" 

This file name contains a question mark (?), which is not recognized as a valid file name character. Therefore, the file name must be enclosed in quotation marks (" "). It must also be in a format that is recognized by the operating system of the remote node you are accessing:

$ COPY BOSTON::"TEST?.DAT" *

A task specification string identifies a program to be executed on the remote node. You can use task specification strings within a program to enable the program to communicate with another program on a remote node. The format used to indicate a task specification string is:

node::"task-spec-string"

This specification identifies the program TEST2 on the remote node BOSTON:

BOSTON::"TASK=TEST2"

There are some restrictions when you copy files to or from an ULTRIX system. For more information, see the OpenVMS Record Management Utilities Reference Manual.

4.2.21 Access Control String Format

Access control strings designate accounts that you can log in to on remote nodes. Node names with access control strings have the following format:

node"access-control-string":: 

Enclose the access control string in quotation marks (" ") and follow it with a double colon (::).

On OpenVMS systems, the access control string consists of a user name, followed by one or more spaces or tabs and a password. For additional information on access control strings, see Chapter 19.

4.2.22 Example

In the following example, BOSTON is the network node name. "HIGGINS ETUHCARAP" is an access control string where:

• HIGGINS is a user name on the node BOSTON.
• ETUHCARAP is the password associated with that name:

$ DIR BOSTON"HIGGINS ETUHCARAP"::WEASEL2:[BORIS]ACCOUNTS.DAT

Use wildcard characters to apply a DCL command to multiple files rather than to one file at a time. The command applies to all files that match the portion of the file specification entered.

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  OSSG Documentation
  22-NOV-1996 13:16:38.78

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