This is a program in Pure Data. See a picture of this diagram in 
http://zzo38computer.cjb.net/PureData/beer_program.png
Or copy the text below to a file called beer_program.pd

#N canvas 14 309 743 575 12;
#X msg 239 28 bang;
#X text 277 29 <-- Click here to start;
#X floatatom 283 183 5 0 0 0 - - -;
#X msg 281 107 99;
#X obj 367 535 print;
#X obj 339 282 - 1;
#X msg 461 370 \$1 bottles of beer on the wall \, \$1 bottles of beer
\, Take