term% cat index.txt PUMP(1) General Commands Manual PUMP(1)
NAME
pump - copy asynchronously via a large circular buffer
SYNOPSIS
pump [ -b iando ] [ -d sleepms ] [ -f ofile ] [ -i ireadsize ] [ -k KB-
buf ] [ -o owritesize ] [ -s start-KB ] [ -S off ] [ -t minutes ] [
file ... ]
DESCRIPTION
Pump copies files (or standard input if none) to standard output by us‐
ing two processes, one reading and one writing, sharing a large circu‐
lar buffer, thus permitting the reading process to get ahead of the
writing process if the output device is slow (e.g., an optical disc).
This in turn can keep the output device busy. The pipeline can approx‐
imate this, but pipe buffering is limited to 64K bytes, which is fairly
modest.
Options are:
-b sets the size of read and write operations to iando bytes. The
default size is 8 kilobytes.
-d causes the output process to sleep for sleepms milliseconds ini‐
tially, giving the reading process time to accumulate data in
the buffer.
-f writes ofile rather than standard output
-i sets the size of read operations to ireadsize bytes.
-k allocates a circular buffer of KB-buf kilobytes rather than the
default 5000 kilobytes.
-o sets the size of write operations to owritesize bytes.
-s prevents output until start-KB kilobytes have been read.
-S seeks both input and output files to off before copying.
-t stops output after minutes have passed. This assumes that pump
can copy 10,584,000 bytes per minute.
EXAMPLES
Append a venti(8) arena to a DVD or BD quickly.
cdfs
venti/rdarena arena0 arena.3 |
pump -b 65536 -k 51200 >/mnt/cd/wd/arena.3
SOURCE
/sys/src/cmd/pump.c
SEE ALSO
cp(1), dd(1), ecp(1), cdfs(4)
BUGS
Pump processes spin while waiting for the circular buffer to fill or
drain.
Dd, ecp and pump occupy slightly different niches but perhaps some sim‐
plification is possible.
PUMP(1)