Re: Start and end of line anchors in middle of regexp

<< No mention to ^ and $. This could perhaps be added. Are they 
 << other known differences between BRE and ERE?
 

 Yes, the GNU sed docs say nothing about ERE treatment of ^ and $. I wrote a book about sed, basically because the sed documentation and other learning resources are rather outdated and poor. In the course of writing the book, I did a LOT of research on sed and regular expressions. Yet I never discovered what you posted. I updated the web site related to the book to add what you found. It's the first correction to the book! I appreciate your finding it. 
 
I would add that BRE and ERE also treat '|' differently. With BRE '\|' is used. But '|' is used with ERE. Otherwise, I do not know any other differences between BRE and ERE. But this has gotten me thinking maybe there are some other differences lurking out there. 
 

 I have no idea about updating the GNU sed manual, but posting as you did might help bring that about. 
 
Thanks, 
Daniel 
 

 PS - I almost posted this to myself, even after my previous explanation. That yahoo interface IS unfriendly.