In Linux, FreeBSD, and NetBSD, , or the always-full device, is a special file that always returns the error code (meaning "No space left on device") on writing, and provides any number of zero bytes to a process that reads from it (similar to ). This device is usually used when testing the behavior of a program when it encounters a "disk full" error. $ echo "Hello, World" > /dev/full bash: echo: write error: No space left on device
History Support for the always-full device in Linux is documented as early as 2007. Native support was added to FreeBSD in the 11.0 release in 2016, which had previously supported it through an optional module called lindev. The full device appeared in NetBSD 8.
Relationship to other special files DeviceRead behaviorWrite behaviorUse case/dev/fullReturns zerosReturns ENOSPCTesting disk full errors/dev/zeroReturns zerosDiscards dataMemory initialization/dev/nullReturns EOFDiscards dataSuppressing output
See also
Fault injection in 9front
References