) {print "hello" if $guest >= 1;unless ($credit > 100) {print "eat\n" unless $food == 0;use 5.010;given ($foo)由于逻辑运算元的作用，还可以写出不用关键字if或unless的判断语句，如常用的打开文件语句：open DATA, '<', $filename or die "Can't open $filename: $!\n";
循环语句.Pe