DIGITAL Command Language

DIGITAL Command Language, abbreviated DCL, is the standard command language for many of the operating systems made by Digital Equipment Corporation. It was first implemented for IAS as the Program Development System, was later added to RSX-11M, RT-11 and RSTS/E, and took its most powerful form in VAX/VMS, later OpenVMS, where VMS Software Inc. still develops it. DCL is a scripting language with strings, integers, bit arrays, arrays and Booleans but no floating point numbers. Scripts reach OpenVMS system services through lexical functions such as F$EXTRACT and F$SEARCH. DCL has IF-THEN-ELSE and access to every Record Management Services file type, but no DO-WHILE or other loop construct, so users write loops with IF and GOTO. A command line begins with a verb followed by parameters and slash-prefixed qualifiers, and commands are defined through Command Language Definition files or as foreign symbols. Versions of DCL also exist for Unix, MS-DOS, OS/2 and Windows, and DCL is the basis of the XLNT language.