tonegen: Generates a sine wave on the sound card or standard out.
-a dB Sets attenuation from "all ones" in dB. Default is "0 db". -d device Sets device name. Default is "/dev/dspW".
If "device" is "-" then it uses STDOUT
-f Hz Sets tone in Hertz. Default is "400 Hz".
-r rate Sets device sample rate in Hertz. Default is "44100 Hz".
-t seconds Sets time to run. Default is infinite.
The length of the tone will run over slightly until full
cycle stops at a "zero crossing" to prevent clicks.