PulseAudio, previously known as Polypaudio, is a sound server for POSIX and WIN32 systems. It is a drop in replacement for the ESD sound server with much better latency, mixing/re-sampling quality and overall architecture.
These tools provide command line access to various features of the PulseAudio sound server. Included tools are:
paplay - Playback a WAV file via a PulseAudio sink.
pacat - Cat raw audio data to a PulseAudio sink.
parec - Cat raw audio data from a PulseAudio source.
pacmd - Connect to PulseAudio's built-in command line control interface.
pactl - Send a control command to a PulseAudio server.
padsp - /dev/dsp wrapper to transparently support OSS applications.
pax11publish - Store/retrieve PulseAudio default server/sink/source
settings in the X11 root window.