sed numbered fields don't start from parenthesis

Hi, 

I believe that the output from the following should be "Sep", not
"28th_Sep".  The result can be changed by adding a ".*" to the 
start of the search string, but I don't think that that should be 
necessary.  Removing the trailing ".*" also produces odd results.  

Using Ubuntu 12.04 LTS. 

$ echo 28th_September_2014 | sed "s/\(sep\).*/\1/i"
28th_Sep

$ sed --version
GNU sed version 4.2.1
Copyright (C) 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is
NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE, to the extent permitted by law.

GNU sed home page: <http://www.gnu.org/software/sed/>.
General help using GNU software: <http://www.gnu.org/gethelp/>.
E-mail bug reports to: <[email protected]>.
Be sure to include the word ``sed'' somewhere in the ``Subject:'' field.
$ 


-- 
testing
bP

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