sed questions aren't Perl question. However, I cannot reproduce your problem: 
$ echo '(3.3.3.3,4.4.4.4,)' | sed 's/,)/)/'
(3.3.3.3,4.4.4.4)
$

[download]
I get that result both for BSD and GNU sed.

In reply to Re: sed deleting file by JavaFan
in thread sed deleting file by ddrew78

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