Regular expression result

[Sébastien N]

Hi,

I write :
echo "TRU 123ZER" | sed 's/.*\([0-9][0-9]*\).*/\1/'
and the result is "3".

Shouldn't it be "123" ?*

Thanx.

[Umapathy S · Accepted solution]

Sebastian,
I think there should a space between first .*

echo "TRU 123ZER" | sed 's/.* \([0-9][0-9]*\).*/\1/'

HTH,
Umapathy

[Brian Bergstrand]

You are running into RE's "match the most I can" policy. You need to break qualify your requirements more.

This should work better:

echo "TRU 123ZER" | sed 's/[^0-9]*\([0-9][0-9]*\).*/\1/'

HTH.

[Sébastien N]

Both are working.
But I don't understand why...


Thanx a lot.

what does HTH mean ?

[Umapathy S]

Sebastian,
As Brian said, "match the most I can" is done by .* which expands to a char followed by any number of chars that include a space also.
The backslashed number represents the group of chars within the braces. Here in your exp you match only the numbers with your braces and thats get printed.
Without spaces all the numbers except 3 is gathered by the first .*.

HTH means Hope This Helps.

HTH,
Umapathy