Dan Track wrote:
On 8/23/06, Cameron Simpson <cs@xxxxxxxxxx> wrote:On 23Aug2006 11:52, Dan Track <dan.track@xxxxxxxxx> wrote: | I've searched and read documents on branching in sed (b) but I still | can't get my head round it. | | Could someone please explain to me how branching works, an example | would be nice. It's like goto. Here's an infinite loop: :foo b foo Cheers, --Hi, Thanks for the info. With that in mind I have the following example I'm having trouble unerstanding. Would you be able to help me out with understanding it? What does the $b in context to the whole file and executing the lines of code on the file. Also what does $!N mean? And do I really need P;D? sed -e '$b /^Target\[[^]]*\][.0-9]*:.*@[0-9.]*$/ { $!N s/^\(Target\[[^]]*\][.0-9]*:.*@\)[0-9.]*\nDirectory\[[^]]*\]: \(.*\)$/\1\2.example.com/ P;D }' text_files/mrtg.cfg > text_files/mrtg.cfg.changed
The sed script quoted is heavily based on an example in the "sed FAQ" (http://sed.sourceforge.net/sedfaq4.html#s4.23.2); reading that document is quite useful for people learning sed I think.
Paul.
