On Tue, Sep 25, 2007 at 07:24:25PM +0300, Giorgos Keramidas wrote: > On 2007-09-24 20:52, Gary Kline <[EMAIL PROTECTED]> 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
The catch is that I don't always know the linecount; the only thing I have found--by examing ALL hundreds of files (briefly:) --is that I was to delete the last 19 lines. If sed can understand negative indexing, then would -e '-19,$d' work? That would makr sense from a human standpoint; not sure how that would fit the sed model, tho. gary > -- Gary Kline [EMAIL PROTECTED] www.thought.org Public Service Unix http://jottings.thought.org http://transfinite.thought.org _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"