COMSPEC
COMSPEC or ComSpec is one of the environment variables used in DOS, OS/2 and Windows, which normally points to the command-line interpreter, which is by default COMMAND.COM in DOS, Windows 95, 98, and ME or CMD.EXE in OS/2 and Windows NT. The variable name is written in all-uppercase under DOS and OS/2. Under Windows, which also supports lowercase environment variable names, the variable name is defined as ComSpec in the environment block, but as COMSPEC inside the DOS emulator NTVDM. When not present in the environment block, the command processor CMD.EXE of Windows NT sets COMSPEC to its own full path; it evaluates COMSPEC, for example, to execute builtin commands in pipelines and to execute command lines with its builtin FOR command.