Re: Delete only the nth block of text, multi-line

Hi,
 "Is the /e (evaluate) option to the s/// command a new addition to sed? And when the expr command is evaluated the very first time, the value of & is null. Is that promoted to a numeric zero when run thru expr?" Yes, the e flag for the s command is a GNU extension. So it perhaps just works with GNU sed.
 

 I was also wondering about how the expr command handles the first time. To my understanding, the first time, "nothing" is substituted, so the following executes, which ends up resulting in 1 (though I don't know exactly why):
 

 $ expr  + 1
1

 

 To make it clearer - so it results in "expr 0 + 1" - the hold space could of course be initialized with 0 at the top of the script, something like.
 

 1 {x; s/.*/0/; x}
 

 Daniel
 



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