This should be an easy one, but for some reason I can't find the docs I
need.  In a bash script, how do you store the return of a program into a
variable?  For instance, I have a dat file:
001
002
003
004
005
006
I want to store the 006 into $six.  I thought I could do something like:

six=tail -n1 numbers.dat

but that didn't work.  What am I missing?  Also, is there a way I can use
a sed command to strip off the leading 00?  TIA!!!

-Brian