Date: Mon, 24 Sep 2007 23:07:20 -0400 From: Howard Goldstein <hg@queue.to> To: Gary Kline <kline@tao.thought.org> Cc: freebsd-questions@freebsd.org Subject: Re: sed question... Message-ID: <46F87B68.6090607@queue.to> In-Reply-To: <20070925013723.GA50027@thought.org> References: <20070925013723.GA50027@thought.org>
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Gary Kline wrote: > My earlier post about deleting the first N lines was answered by > this one-liner site {below}. I wasn't including any > redirection; doing so finally resolved the problem. Now I need > to delete every line from the 19th or so to the last line. > Question one, can anybody explain the following syntax? What do > "P", "D" "ba" represent, in other words? > > > # delete the last 10 lines of a file > sed -e :a -e '$d;N;2,10ba' -e 'P;D' # method 1 > sed -n -e :a -e '1,10!{P;N;D;};N;ba' # method 2 > > > Question two, can sed do its thing inline? Wouldn't it be easier to use head -n 18 ?
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