what should egrep '|root' /etc/passwd print? (Everything)

[Ozan Yigit]

In article <8492 at smoke.ARPA> Doug Gwyn  writes:
>In article <44414 at beno.seismo.CSS.GOV> Rick Adams writes:
>>What should 
>>	egrep '|root' /etc/passwd
>>print?
>
>The question of how to handle empty strings in regular expressions
>does not have a clear-cut answer.  

Oh ??? Just what does '(foo)?' match on your egrep ?? It just happens
to be the same thing as E|foo (E for Epsilon, or the null match),
or exactly what rick wants to match. It had a clear cut answer before,
but I am sure it is lost somewhere along the line. 

> .."sam", which has the most powerful
>regular expression mechanism of any of the editor-like programs I use,
>says the following:
>	?no operand for `|'

A parsing glitch no doubt. See, some expressions are more regular :-)
then others, so "sam" will no doubt accept the expression under a
disguise of "(foo)?". 

In any case, Rick should probably use jaw-improved-gnu-egrep for
correct results.

oz
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