"Remember the "bad old days", when users had a CLUE (Command
Line User Environment) and PC speakers went beep, beep? That all
changed in the mid-1980s, when Apple gave us the Mac, and Commodore
introduced its Amiga. ... On the flip side of the coin, one of the
nice things about Linux is that it allows you to recycle all of
your old equipment. ... Therefore, it's not uncommon to find
Linux-based machines running *without* sound cards."
"If this happens to be your scenario, does this mean that you
have to forego sound entirely? Of course not! It's time to remember
an old friend, the internal speaker. No sound card is required;
just a PC with a regular speaker in its case."
"This doesn't mean that you have to be content with mere beeps,
however. Instead, you'll progress well beyond the standard
"bell" sound (ASCII code 007, or Ctrl-G). Using low-grade wizardry,
you'll be able to vary the pitch and length of each tone. As such,
you'll soon have the ability to play a simple melody by typing a
few brief commands. It will also be trivial to include these sounds
within your programs."