2.1. More about semicolons
A perl program can naturally include more than one command. To do so, you need to place a semicolon at the end of each command or otherwise the interpreter will be confused.
It is not enough to put each command on a separate line. In fact it's not even necessary. The following two programs are equivalent:
print "One Fish,\n"; print "Two Fish,\n"; print "Red Fish,\n"; print "Blue Fish.\n";
and
print "One Fish,\n"; print "Two Fish,\n"; print "Red Fish,\n"; print "Blue Fish.\n";
However, for readability and easy debugging it is recommended that each statement will be on a separate line. And sometimes it's helpful to span one on more than one line.