OT: simple regex question

[Jacques B.]

On 4/23/07, Dario Lesca <d.lesca at solinos.it> wrote:
> Hi, how to found into string 2 or more word, only if are all present?
>
> % echo "aa bb cc dd"|egrep -q '(bb|dd)' && echo found
>
> This command show "found" if bb OR dd are in string.
> But if I want show "found" only if bb AND dd are present into string.
>
> What egrep (or sed) command I must use?
>
> Many thanks for your reply!
>
> --
> Dario Lesca <d.lesca at solinos.it>
>
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Will this do?

echo "aa bb cc dd" | grep bb | grep -q dd && echo found

Not as clean because you are calling two greps instead of one.  But it
do what you seem to want to do.  You can't use the -q on the first
grep pipe because you need that output to feed into the second grep
pipe.

I don't know perl well at all so can't give input on that solution
other than when I tested it with only one matching expression (i.e.
echo "aa bb cc ed"), it still came back as found.  I have a perl book
and had a quick look to see if I could figure it out but no such luck.

Jacques B.