改

#!/usr/bin/perl
$|=1;
$how = 8; #文字数
print 'Content-Type: text/plain', "\n\n";
for (1..$how) {
if(($i = int(rand(3))) == 0){ printf('%c', (int(rand(10)) + 48)); }
elsif($i == 1){ printf('%c', (int(rand(26)) + 65)); }
elsif($i == 2){ printf('%c', (int(rand(26)) + 97)); }
}
exit;