THROTTLE 1.2

throttle − bandwidth limiting pipe

throttle [−l fifo | −t fifo ] [−s blocksize ] [−w window ] [−bkmBKM] limit

throttle copies the standard input to the standard output while limiting bandwidth to the specified maximum.

limit

The bandwidth limit in bits, kilobits, megabits, bytes, kilobytes or megabytes per second depending on the options −bkmBKM.

−b, −k, −m

Set the limit unit to bits, kilobits, or megabits per second.

−B, −K, −M

Set the limit unit to bytes, kilobytes, or megabytes per second.

−s blocksize

Set the I/O block size to blocksize bytes. Initially the block size is 512.

−w window

Window of time in seconds used for limit calculation. Initially the window is 60 seconds.

−l fifo

Create fifo and listen for change option messages.

−t fifo

Transmit options to existing throttle process.

−q

Run quietly.

−v

Print informational messages to stderr at window intervals.

−V

Print the version number and copyright and exit.

−h

Display help and exit.

If SIGUSR1 is received by a running throttle process, it will print statistics to stderr without waiting for the next window and regardless of the verbose option setting.

If SIGUSR2 is received, the fifo will be checked for option change messages without waiting for the next window.

To limit the bandwidth of a tar back-up to a remote server to 1 Mbit/s, type:

$ tar czf - . | throttle -m 1 | ssh host ’tar xzf - -C /bak’

To start a pipeline which can by dynamically controlled with throttle:

$ ... | throttle -l /tmp/throttle.ctl -m 1 | ... &

This command will start up throttle communicating through the named fifo /tmp/throttle.ctl. In order to send change options to this throttle process, you would need to run another throttle command as:

$ throttle -t /tmp/throttle.ctl [OPTIONS TO CHANGE]

Specifying a bandwidth limit greater than the rate of incoming data will not increase the speed of the pipeline.

James Klicman <james at klicman dot org>

throttle-1.2.tar.gz
throttle-1.2-1.src.rpm

Previous releases:
throttle-1.1.tar.gz
throttle-1.1-1.src.rpm
throttle-1.0.tar.gz

An entertaining use of throttle is playback of VT100 animations on modern (fast) terminals.

$ clear; throttle -s 1 -b 9600 <movglobe.vt

More VT100 animations are available at http://artscene.textfiles.com/vt100/.