Date: Thu, 2 Feb 2012 01:51:56 -0600 (CST) From: Robert Bonomi <bonomi@mail.r-bonomi.com> To: freebsd-questions@freebsd.org Subject: Re: some kind of binary sed(1) command Message-ID: <201202020751.q127puMO011247@mail.r-bonomi.com> In-Reply-To: <20120202062236.GA3419@tinyCurrent>
next in thread | previous in thread | raw e-mail | index | archive | help
> From owner-freebsd-questions@freebsd.org Thu Feb 2 00:27:33 2012 > Date: Thu, 2 Feb 2012 07:22:36 +0100 > From: Matthias Apitz <guru@unixarea.de> > To: freebsd-questions@freebsd.org > Subject: some kind of binary sed(1) command > > > Hello, > > I have a normal ASCII file wich has in some places two lines of '*', > separated by an empty line, i.e. > > ....\n > *********************\n > \n > *********************\n > ....\n > > and I want to substitute the \n between the star lines by \f; the > 'binary' sed command would just be > > s/*****\n\n*****/*****\n\f*****/ > > which ofc does not work with sed(1) because it is line oriented; > I could write something in perl, C, awk or whatever language, but I > would prefer to do it with the normal commands... any ideas? <lightbulb mode="on"> Use sed. </lightbulb> *GRIN* As follows: sed -e ' t l :l /^[*]+$/ { N !/\n$/ { P s/^.*\n// t l } /\n$/ { N !/\n\n[*]*$/ { P s/^.*\n// P s/^.*\n// t l } /\n\n[*]*$/ s/\n\n/\n\f/ } }' Note: "how" this incantation works is left as an excercise for the student. Careful perusal of the FM will provide enlightenment. Caveat: this will convert: {stars} {blank} {stars} {blank} {stars} to; {stars} {formfeed} {stars} {blank} {stars} not: {stars} {formfeed} {stars} {formfeed} {stars}
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201202020751.q127puMO011247>