On Mon, Sep 24, 2007 at 11:07:20PM -0400, Howard Goldstein wrote: > 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 '$d;N;2,10ba' -e 'P;D' # method 1 > > sed -n -e :a -e '1,10!{P;N;D;};N;ba' # method 2 > > > > > > Question two, can sed do its thing inline? > > Wouldn't it be easier to use head -n 18 ? >
No, because most of these files are between 40 and 50 lines. I only care about the first 30 or 40; everything below has to be deleted. By hand, using vi, I might type :31,$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. -- 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]"