Null device
In some operating systems, the null device is a device file that ignores anything written to it but returns that the write worked. This device is called /dev/null
on Unix and Unix-like systems, NUL:
or NUL
on CP/M and DOS (internally \DEV\NUL
), nul
on newer Windows systems[1] (internally \Device\Null
on Windows NT), NIL:
on Amiga systems,[2] and NL:
on OpenVMS.[3] In Windows Powershell, the equivalent is $null
.[4] It returns nothing to any process that reads from it, returning EOF immediately.[5] In IBM DOS/360, OS/360 (MFT, MVT), OS/390 and z/OS operating systems, such files would be assigned in JCL to DD DUMMY
.
References
- ↑ "Redirecting Error Messages from Command Prompt: STDERR/STDOUT". support.microsoft.com. Retrieved 2020-03-06.
- ↑ Commodore-Amiga, Inc. (1986). The AmigaDOS Manual. Bantam Books. p. 12. ISBN 0-553-34294-0.
- ↑ "OpenVMS Programming Concepts Manual". h30266.www3.hpe.com. Archived from the original on 2020-07-02. Retrieved 2020-03-06.
- ↑ SteveL-MSFT. "about_Automatic_Variables - PowerShell". docs.microsoft.com. Retrieved 2020-03-06.
- ↑ "Single Unix Specification Section 10.1: Directory Structure and Files". The Open Group. Retrieved 2012-11-29.