If stripping leading blanks is okay, then you can use #withBlanksTrimmed. 
Otherwise you can use the following oneliner:

string copyFrom: 1 to: (string lastIndexOfAnyOf: CharacterSet nonSeparators startingAt: string size ifAbsent: string size)

Levente

On Tue, 22 Sep 2015, Casimiro - GMAIL wrote:

> I have a ByteString line. I want to strip blanks and tabs at end of it. Blanks and tabs allowed between words. MxMatcher looks a bit like using a gun to kill a fly. Any suggestion about a time effective way
> of solving the problem? (obvious way: asOrderedCollection and then backtrack killing spaces & tabs until find non space/tab char).
> 
> Best regards,
> 
> CdAB
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