In Unix-like operating systems, /dev/null or the null device is a special file that discards all data written to it but reports that the write operation succeeded. It provides no data to any process that reads from it, yielding EOF immediately.
This concept is roughly equivalent to the NUL: or just NUL device of CP/M, DOS and Windows, the \Device\Null of Windows NT and its successors or use NUL abreviation, the NIL: of Amiga operating systems, and the NL: of OpenVMS. In Windows Powershell, the equivalent is $null.
References in computer culture
This entity is a common inspiration for technical jargon expressions and metaphors by Unix programmers, e.g. "please send complaints to /dev/null", "my mail got archived in /dev/null", and "redirect to /dev/null"—being jocular ways of saying, respectively: "don't bother sending complaints", "my mail was deleted", and "go away". The iPhone Dev Team commonly uses the phrase "send donations to /dev/null", meaning they do not accept donations. The fictitious person name "Dave (or Devin) Null" is sometimes similarly used (e.g., "send complaints to Dave Null"). In 1996, Dev Null was an animated virtual reality character created by Leo Laporte for MSNBC's computer and technology TV series, The Site. A 2002 advertisement for the Titanium PowerBook G4 reads The Titanium Powerbook G4 Sends other UNIX boxes to /dev/null. 
The null device is also a favorite subject of technical jokes, such as warning users that the system's /dev/null is already 98% full. The April Fool's, 1995 issue of the German magazine c't reported on an enhanced /dev/null chip that would efficiently dispose of the incoming data by converting it to a flicker on an internal glowing LED.
- Filesystem Hierarchy Standard
- Memory hole
- rm (Unix)
- Standard streams
- Unix philosophy
- Write-only memory
- "Single Unix Specification Section 10.1: Directory Structure and Files". The Open Group. Retrieved 2012-11-29.
- Jargon file entry for "bit bucket"
- The Linux Kernel Archives FAQ at kernel.org
- "The FreeBSD Funnies". Freebsd.org. Retrieved 2012-11-28.