Hi,
I've seen something similar to this while using "gnu grep". If you simply grep for something, only those lines containing the search-pattern will be displayed. But if u issue "gnu grep -1 'search-pattern' file", you will get the lines immediately before and after the line containing the search-pattern.

In your case, it gives the line just before the line containing search-pattern, i guess.

There is a chance that your "egrep" may be aliased to "gnu egrep", or at least you are using the version of egrep inside the gnu folder.

It would be kind of you, if you would explain the functionality of "-B" option. I wasnt able to ascertain..

Thanks,
Srini