smixer is a command-line and scriptable program to control and display the mixer volume levels on a sound card in linux.
Distrubution of smixer is under the GNU GPL. See the "COPYING" and/or smixer.c file for more information.
Usage is explained very good in the man page.
smixer may be invoked with the following command-line options:
-a When printing current settings include all devices.
-p Print out the current mixer settings, then exit.
-f file Process commands from file, then exit.
[no options] Process commands from stdin (interactive or from a pipe), then exit.