Null device

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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[change | change source]

  1. "Redirecting Error Messages from Command Prompt: STDERR/STDOUT". support.microsoft.com. Retrieved 2020-03-06.
  2. Commodore-Amiga, Inc. (1986). The AmigaDOS Manual. Bantam Books. p. 12. ISBN 0-553-34294-0.
  3. "OpenVMS Programming Concepts Manual". h30266.www3.hpe.com. Retrieved 2020-03-06.
  4. SteveL-MSFT. "about_Automatic_Variables - PowerShell". docs.microsoft.com. Retrieved 2020-03-06.
  5. "Single Unix Specification Section 10.1: Directory Structure and Files". The Open Group. Retrieved 2012-11-29.