Here's a slight alternative to the solution:

mysql -u uname dbname -e "show tables" | grep -v Tables_in | grep -v "+" | \ gawk '{print "drop table " $1 ";"}' | mysql -u uname dbname

From my mysql drop all tables using single command.

I'm not sure if there's any good reason to use one or the other. Obviously some command line options (like username) are missing from mine...