Update: Abstraction is correct. Assigning to the same var works too. Also, if you use tr you may have problems with wide characters.

You should assign the result of uc(...) to another variable.

$name = "world";
$uc_name = uc($name);
print $uc_name,$/;
[download]

if you want to change the case of the current variable, you could use tr.

$name = "world";
$name =~ tr/[a-z]/[A-Z]/;
print $name, $/;
[download]

--
hiseldl
"Act better than you feel"