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 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 COMSPEC inside the DOS emulator NTVDM and for any DOS programs, and ComSpec under CMD.EXE.