sed syntax

[Matt Price]

ok

after all these years with linux i still have all kinds of trouble with
regexp's.  i have a file full of error messages from dmesg:

[125559.165041] Buffer I/O error on device sda5, logical block 19698429

(i know, it's not a good sign; i'm just trying to hang onto this drive
for a little longer)

i want to cut these lines back so i just have the block number:
19698429

now, i know i can do that with 'cut -d " " -f 10', but my first impulse
was to do it with sed, and i, as usual, don't understand what i'md doing
wrong.  since i just want the final 8-digit block number, i thought i
could do this:
cat file | sed 's/(^.*)([0-9]*$)/\2/' 

but that returns the initial file unmodified.  

any ints out there?  thanks as always,

matt


-- 
Matt Price
matt.price-H217xnMUJC0sA/PxXw9srA at public.gmane.org
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