Control Sound Volume
You can use
amixer to control the sound volume, e.g.
amixer set 'Master' 50%
amixer set 'Master' 10%+
amixer set 'Master' 2dB-
You may need to set the soundcard using e.g.
-c 1 for the second soundcard, see
Sounds can be played using a player like
You might want to have a look at this question: Where do I find system sounds?
Display On-Screen Notification
You can reproduce the on-screen notification using the X On-Screen Display library XOSD. The package is called
xosd-bin and the command
osd_cat is used to display text, status bars etc. on the screen.
osd_cat -b percentage -P 20 -T Status: -f "-adobe-helvetica-bold-*-*--34-*-*-*-*"
See this German wiki page for options and examples and
man osd_cat for more.