Removing unique elements from string I came upon this question, because it seems to be very common use-case to find unique characters in string. But what if we want to get rid of them?

Input contains only lower case alphabets. Only letters from a to z are used. Input length may be from 1 to 1000 characters.

Example:
input: helloworld
output: llool

Objective: Shortest code wins
Language: Any of the top 20 of TIOBE languages
(GolfScript, 15 13 characters)
:;{.;?);&gt;?)},

GolfScript is not one of the top 20, but a codegolf without GolfScript... (run it yourself)
Previous Version:
(run script)
1/:;{;\-,;,(&lt;},