Either I do something wrong or there is a regexp bug in sed !!

Brandon S. Allbery KF8NH allbery at ece.cmu.edu
Sun Nov 14 15:48:31 PST 2004

On Sun, 2004-11-14 at 18:39, Zoltan Frombach wrote:
> match anything! After spending like an hour investigating this, I realized 
> that the + after my bracket expression ( I'm talking about this part here: 


> According to the sed man page, the regexp syntax that is used by sed is 
> documented in the re_format man page. And according to the re_format man 
> page: "A piece is an atom possibly followed by a single= `*', `+', `?', or 

You need to read it more carefully.  There are two kinds of regular
expressions, "basic" and "extended".  sed, ed, and grep speak BRE
syntax, whereas awk and egrep speak ERE syntax.  + is special only in
ERE syntax.

(And then there's GNU, where the difference between BRE and ERE is that
some things use a preceding backslash in BRE and don't in ERE, and vice
versa, so GNU sed does what you want if you use \+ instead of +.)

brandon s. allbery    [linux,solaris,freebsd,perl]     allbery at kf8nh.com
system administrator      [WAY too many hats]        allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon univ.         KF8NH

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