Command Prompt (Windows) - cmd.exe is the command line interpreter on Windows NT-based operating systems (including latest Windows and Windows Server).
It is the analog of COMMAND.COM in MS-DOS and Windows 9x systems, or of the Unix shells (bash, ksh, zsh, ...) used on Unix-like systems.
See a command-line reference.
The Practical Extraction and Reporting Language
Perl was and is developed on Unix, of course, but there have been a couple of Win32 ports. One is compiled using Cygwin (appdb entry); the other is provided by ActiveState and compiled using Visual C++. Total perl compatibility might make it easier to run or port hybrid applications that include a Win32 binary componenent and a perl component.