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 (internally \Device\Null on Windows NT), NIL: on Amiga systems, and NL: on OpenVMS. In Windows Powershell, the equivalent is $null. It returns nothing to any process that reads from it, returning EOF immediately. 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.

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Category:Unix