TRUENAME is an undocumented command in the MS-DOS command interpreter starting with version 5.0. It is also present in the command interpreter packaged with Windows 95 and 98, but not NT or later.
TRUENAME interprets its argument as a partial path name and outputs the equivelent full path name, regardless of the actual existence of such a file. The period and double-period directory placeholders are expanded appropriately, and asterisks are expanded to question marks. A "/?" argument, standard in more recent versions of DOS to indicate a request for command parameter information, yields a totally unhelpful message.
I am not certain of the intended purpose of such a command.