[Unix] A special case of a {filter} that reads its entire input
before writing any output; the canonical example is a sort utility.
Unlike most filters, a sponge can conveniently overwrite the input
file with the output data stream. If a file system has versioning (as
ITS did and VMS does now) the sponge/filter distinction loses its
usefulness, because directing filter output would just write a new
version. See also {slurp}.
[glossary]
[Reference(s) to this entry by made by: {filter}{slurp}]