- MS-DOS (Wikipedia)
MS-DOS (/ˌɛmˌɛsˈdɒs/ em-es-DOSS; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as “DOS” (which is also the generic acronym for disk operating system). MS-DOS was the main operating system for IBM PC compatibles during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.
- cat (Unix) (Wikipedia)
cat is a standard Unix utility that reads files sequentially, writing them to standard output. The name is derived from its function to (con)catenate files (from Latin catenare, “to chain”). It has been ported to a number of operating systems. ¶ The other primary purpose of cat, aside from concatenation, is file printing — allowing the computer user to view the contents of a file. Printing is the most common use of cat.