I've been banging my head against the wall to accomplish the following. Given two files:

File a.txt

12345 hello
32324 there

File b.txt

12345 stuff
45454 howdy
32324 joe

If column 1 matches between the two files, then print only the entire line of the 2nd file (b.txt in this example So the desired output in this case would be:

12345 stuff
32324 joe

I've been working with the follow as a basic start, but seem to have come up with every combination except that which I'm looking for:

awk 'NR==FNR{++a[$1];next}!a[$1]' a.txt, b.txt > c.txt

As you probably guessed this is based on an 'almost' solution google search - in the meantime I've purchased the O'Reilly book and am plowing through it - but in the meantime I really need to get this done... so, anyone kind enough to share a (hopefully somewhat commented) snippet would be most appreciated.

Thanks,
Al

awk 'NR==FNR{++a[$1];next} $1 in a' a.txt b.txt > c.txt

Thanks, just what I was looking for!
Al

if you have a sorted files then you can go for much simpler command like "comm"