sub trimTo {
    my ($line, $length) = @_;
    $line=~s/([^ \s]{$length})([^ \s])/$1...\n$2/g;
    return $line;
}

[download]
Though only the first line is 30, and the rest is 31 chars, i think it's more or less doing what you search for ?
It also makes sure strings that are exact 30 length dont have dots added.

I just saw Jaspers solution, it's a bit different, i thought i post it anyway.

Addition:
Code isn't doing what was expected. Sorry Kiat :-)

In reply to Re^2: In search of a better way to trim string length by Vennis
in thread In search of a better way to trim string by kiat

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