Rexx
Rexx (REstructured eXtended eXecutor) is a programming language developed between 1979 and 1982 by M. F. Cowlishaw. Although Cowlishaw, who is an IBM employee, developed the language in his spare time, IBM soon recognized the usefulness of the language and introduced it in 1982 into the operating system VM/CMS as its main scripting language. Around the same time IBM's CMS editor, XEDIT, was extended so that edit macros could be written in Rexx.
At present IBM includes support for the language in almost all its operating systems. Non-IBM freeware versions are available for MS-Windows, most variants of Unix, and Mac OS X.
Keywords characterizing the language are: Flat learning curve, procedural, interpreted, untyped (or rather one type: character string of arbitrary length), support of numbers of arbitrary precision, associative arrays, strong support of character string parsing, invokable from different environments, passes commands to its invoking environment.