From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3)
Gecko/20041020

Description of problem:
Grep does not recognise beginning of a line when using the "matching
part" switches. If the line really matches the given pattern, then
grep tries to match the pattern in the line with the last match
deleted (try the following line: 
 $ echo aa | grep -o ^a
Expected result is
 a
while grep gives
 a
 a
which is a bug. Similarly,
 $ echo ab | grep -o ^.
should return
 a
but returns
 a
 b


Version-Release number of selected component (if applicable):
grep-2.5.1-31.2

How reproducible:
Always

Steps to Reproduce:
1. Run grep -c or grep -o. Use the special character ^ in the regular
expression.
2. If there is a matching line that contains the pattern more than
once with no other characters between the matches, all the matches are
written out.

Additional info: