What is "mexscript"

MexScript is a multi-paradigm computer scripting language used in a number of game resource archive file handlers. It was originally created for the 16-bit command-line tool multiex, and later 32-bit versions of MultiEx Commander. It is a script that enables the end user to have the interpreting program perform a number of tasks needed to access file contents, as well as to replace file contents. The MexScript has since become one of the standards to process game archives, as is indicated by the implementation of the script (also referred to as multiex, MexCom3, BMS) in similar programs, such as Dragon UNpack, Game Extractor, FusePAK, and the more recent dialect QuickBMS.