The interpreter is the "engine" that executes scripts.
For batch files, the interpreter is included with every DOS, Windows and OS/2 operating system: cmd.exe and/or command.com (the "MS-DOS prompt" or "Command Prompt").
EDIT (MS-DOS), Notepad (Windows), E (OS/2), or any other ASCII editor will do.
Basically, a batch file is just an ASCII text file with a ".bat" extension, containing (DOS) commands.
The closest to a batch file IDE is Dr.Batcher, but by the very nature of the batch language it does not (and cannot) come with a debugger.
Several "batch-aware" editors are available.
For debugging batch files without advanced tools, read my batch debugging page.
In Windows 2000, on the command line, type HH windows.chm::ntcmds.htm, or in Windows XP, type HH ntcmds.chm.
For MS-DOS 5 and later, Windows 95 and later, or OS/2 2.0 and later, on the command line, type HELP for a list of available commands.
To get help for any of these commands, type HELP followed by that command.
For Windows NT 4 and later I wrote AllHelp.vbs; run it once to create an HTML file containing all available help text for every command available in your Windows version, and in your system's language.