[Newbies] Remove trailing spaces of aString

[H. Hirzel]

Hello

I use Squeak 4.3, Update 11860.

I want to remove the trailing spaces and or tabs and LF of a String

something like
'abc
'

should just be
'abc'.

If I remember  that there was a method in class String to something
like this. Is this correct?
Is there a package with additional String convenience methods?

Thank you for the answer in advance
--Hannes