>>291
/usr/ports/misc/mbuffer ってのもあるみたい。

mbuffer is a tool for buffering data streams. It is also a raplacement
for buffer with additional functionality:

- display of i/o speed
- optional use of memory mapped i/o for huge buffer files
- multithreaded instead of sharedmemory ipc
- multi-volume support
- auto-loader support
- network support
- buffer compatible command-line options

WWW: http://www.maier-komor.de/mbuffer.html