In command.com, the message Bad command or file name indicates a "syntax error" message, which had its origins in the BASIC interpreters of the 1980s. Most often, this error message results from mistyping a command to be executed. Novices, in general, and quite a few experienced users as well, had trouble understanding the message, so later GUI operating systems changed this message; for instance, OS/2 and the Windows NT family use is not recognized as an internal or external command, operable program or batch file.

Bash, a variant of the Bourne shell designed for GNU and used on various UNIX-like operating systems, produces the similar : command not found.

See also

• Abort, Retry, Fail?