sed question...

Gary Kline kline at
Mon Sep 24 18:37:24 PDT 2007

	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?

	thanks in advance,


  Gary Kline  kline at  Public Service Unix

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