Date: Tue, 25 Sep 2007 19:24:25 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Gary Kline <kline@tao.thought.org> Cc: Howard Goldstein <hg@queue.to>, freebsd-questions@freebsd.org Subject: Re: sed question... Message-ID: <20070925162424.GA13463@kobe.laptop> In-Reply-To: <20070925035217.GC50519@thought.org> References: <20070925013723.GA50027@thought.org> <46F87B68.6090607@queue.to> <20070925035217.GC50519@thought.org>
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On 2007-09-24 20:52, Gary Kline <kline@tao.thought.org> wrote:
>On Mon, Sep 24, 2007 at 11:07:20PM -0400, Howard Goldstein wrote:
>>> # delete the last 10 lines of a file
>>> sed -e :a -e '$d;N;2,10ba' -e 'P;D' # method 1
>>> sed -n -e :a -e '1,10!{P;N;D;};N;ba' # method 2
>>>
>>> Question two, can sed do its thing inline?
>>
>> Wouldn't it be easier to use head -n 18 ?
If you _know_ that the file has 28 lines, yes. If you don't,
then itmay be tricky to 'guess' that -n 18 is the right option.
> No, because most of these files are between 40 and 50 lines. I only
> care about the first 30 or 40; everything below has to be deleted. By
> hand, using vi, I might type :31,$d that fixes that one file. Of
> course, I could simply edit in "19" for "10" above. It would be more
> savvy to understand the sed syntax.
You don't need to manually edit files with vi(1) if all you want to do
is type ``:31,$d<RET>:wq<RET>'' ...
sed -i '' -e '31,$d' file.txt
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