HP OpenVMS Systems Documentation
OpenVMS User's Manual
2.9.1 Default Actions
A default is the value supplied by the operating system when you do not
specify one yourself. For example, if you do not specify the number of
copies as a qualifier for the PRINT command, the system uses the
default value 1. The operating system supplies default values in
several areas, including command qualifiers and parameters. The
defaults that the operating system uses with specific commands are
described in each command's entry in the OpenVMS DCL Dictionary.
The system responds to some commands by displaying information in a system message about what it has done. For example, when you use the PRINT command, the system displays the job identification number it assigned to the print job and shows the name of the print queue the job has entered.
Not all commands display informational messages. Successful completion
of a command is usually indicated when the DCL prompt returns.
Unsuccessful completion is always indicated by one or more error
If you enter a command incorrectly, the system displays a system message and prompts you for the correct command string, as the following example shows:
You can also receive system error messages during command execution if the system cannot perform the function you have requested. For example, if you type a PRINT command correctly but the file you specify does not exist, the PRINT command informs you of the error with a message like the following:
The first message is from the PRINT command. It tells you it cannot
open the specified file. The second message indicates the reason for
the first; that is, the file cannot be found. RMS
refers to the OpenVMS file-handling software, Record Management
Services; error messages related to filehandling are generally OpenVMS
If you suspect that your process is not doing what you think it should be doing, press Ctrl/T. Ctrl/T displays a single line of statistical information about the current process. The statistical information includes node and user name, current time, current process, central processing unit (CPU) usage, number of page faults, level of I/O activity, and memory usage, which is listed in number of CPU-specific pages.
When you press Ctrl/T during an interactive terminal session, it momentarily interrupts the current command, command procedure, or image to display statistics. Although Ctrl/T disrupts the characters on the screen, it does not affect any procedure or editing session. For example, if a user named MCCARTHY on node GREEN presses Ctrl/T while using the EVE editor, the following line is displayed in the EVE message window:
Ctrl/T is disabled by default. If you know your system is running and
Ctrl/T does not display statistical information, you can enable Ctrl/T
with the DCL command SET CONTROL=T. Enter the command at DCL level (at
the dollar sign ($) prompt), then press Ctrl/T again. Ctrl/T will
remain in effect for the duration of your process, unless it is
disabled from a program or command such as SET NOCONTROL=T. Note that
your terminal must be set to BROADCAST mode for Ctrl/T to display on
your screen. BROADCAST mode controls whether reception of broadcast
messages (such as those issued by MAIL and REPLY) is enabled. To set
your terminal to BROADCAST mode, enter the DCL command SET
TERMINAL/BROADCAST at the DCL prompt.
When you are logged in to the operating system, you can obtain
information about using the system and available commands by using the
HELP command. You can also get help on system messages by entering the
HELP/MESSAGE command as shown in Section 2.10.3.
Use the following procedure to get help on OpenVMS commands and utilities:
The following example shows the commands that you would enter to look for help about the SHOW USERS command:
2.10.2 Getting Help on Specific Commands
If you know the command you need information about, enter HELP and the command name. For example, to get help about the SHOW USERS command enter the following command:
If you need help but do not know what command or system topic to specify, enter the command HELP with the word HINTS as a parameter. Each task name listed in the HINTS text is associated with a list of related command names and system information topics.
The OpenVMS DCL Dictionary contains more information about the HELP command.
Use the Help Message utility (MSGHLP) to get online help for system messages. To display information on how the last command completed, type:
You can also display information about a specific message by including the message identifier or words from the message text. For example:
A message and its description can also be accessed by entering the message status code. For example:
The Help Message utility allows you to update the messages database
with your own messages or to add comments to existing message
descriptions. You can also extract a subset of messages from the
messages database to create and print your own customized messages
documentation. For details on how to use the Help Message utility, see
OpenVMS System Messages: Companion Guide for Help Message Users.
When you finish using the system, always log out. This prevents unauthorized users from accessing your account and the system. It is also a wise use of system resources; the resources you no longer need are available for other users.
To log out, enter LOGOUT at the DCL prompt. For example:
The system displays a message, similar to the following message, confirming that you are logged out of the system:
You can log out of the system only when you are at the DCL prompt ($).
You cannot enter the LOGOUT command while you are compiling or
executing a program, using a text editor (such as EDT or EVE), or
running a utility (such as Mail). First you must exit the program,
editor, or utility. When the system displays the DCL prompt, you can
To find out how much time you spent at the terminal (elapsed time), how much computer time you used (charged CPU time), and other accounting information, enter LOGOUT/FULL at the DCL prompt. For example:
The system displays information similar to the following:
2.11.2 Ending a Remote Session
You can end a remote session in two ways:
When you end a remote session, the system displays the message
"%REM-S-END, control returned to node NODENAME::" and returns
you to the process on the system from which you made the remote node
If a DECnet network connection to a remote system is lost, DECnet will
retransmit your data in an attempt to reestablish communications. If
DECnet is unable to reestablish communications within a predetermined
timeout period, your connection to the remote system is terminated and
the system displays the message "Path lost to partner."
Logging out of a session conserves system resources and protects your files. Leaving a terminal on line represents one of the greatest sources of inside break-ins. When you leave your terminal on line and your office open, you have effectively given away your password and your privileges and have left your files and those of the other members of your group unprotected. Any user can easily and quickly transfer all files accessible through your account. A malicious insider could rename and delete your files and any other files to which you have write access. If you have special privileges, especially privileges in the Files or All category, a malicious user can do major damage.
Log out when you leave your office even for a brief period of time. If
you have performed remote logins, you must log out of each node.
Clear your screen each time you log out of a terminal to ensure that your user name, node name, and operating system are not revealed to anyone else. If you are logging out after a remote login, the name of the node to which you return (the local node) is also revealed. If you access multiple accounts remotely over the network, the final sequence of logout commands reveals all the nodes and user names that are accessible to you on each node (excluding the name of the furthest node reached). To those who can recognize the operating system from the prompt or a logout message, these displays also reveal the operating system.
After the screen clears, the cursor is positioned at the top of the screen, next to the DCL prompt. Enter the DCL command LOGOUT at the prompt. The only information remaining after you log out is your logout command and the logout completion message. For example:
2.12.2 Disposing of Hardcopy Output
After you log out from a hardcopy terminal, remove, file, or dispose of all hardcopy output that might reveal sensitive information. Your security administrator should provide direction on preferred procedures. Many sites use paper shredders or locked receptacles for this purpose. Handle output that you plan to save just as carefully.
You should also dispose of hardcopy output if the system fails before
you log out. In addition, if you will not be present when the system is
initialized, turn your terminal off.
Your security administrator might ask you to break the connection to a dialup line when you log out. If you anticipate no further immediate use of the line, use the LOGOUT command with the /HANGUP qualifier. The /HANGUP qualifier directs the system to automatically break the connection to the dialup line after you log out.
Breaking the connection to a dialup line: