DCL Programming

Course Length: Approximately 40 hours
Prerequisites: The student should be familiar with VMS concepts and have some programming experience in another procedural language.

The DCL Programming course is designed for the System Manager or Operator who needs to use the language on a day to day basis. The Digital Command Language (DCL) is the primary user interface to the VMS operating system. DCL uses commands to examine and change operational characteristics of the user's process and the system. Sequences of DCL commands can be saved in files (command procedures) and the contents of the files executed.

Command procedures are used extensively in system operations and maintenance. Functions such as starting up and shutting down the system, installing new software products, modifying system parameters are all performed through the use of command procedures.

This course treats DCL primarily as a programming language.

First, the components of the DCL command line are introduced: labels, commands, parameters, qualifiers, comments, and line continuations are defined. Details of DCL language are covered. The string and numeric data types are discussed, as well as the operations that can be performed on the values. An overview of lexical functions and the details of some commonly used functions are then presented. The final unit deals with command procedures. Emphasis is on those commands that support the use of command procedures - transferring execution flow, error handling, performing device and file I/O.

At the completion of this course, the student will be able to:

• Name and describe the main components of a DCL command line
• Name and describe the data types available in DCL
• Define, use, display and delete local and global symbols
• Describe and use lexical functions
• Read, write, execute and debug DCL command procedures
• Incorporate parameter passing, I/O commands and error handling into command procedures

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Note: All computer based training courses are Y2K (Year 2000) compliant.