1. does anyone know the good book that I can use to start?
That depends a bit on the KSH dialect you are using, but 'Learning the Korn Shell' (Bill Rosenblatt - O'Reilly) should get you going. It is based on ksh88, but I never had any trouble with pdksh (most unix distro's carry this one).
I also have the 'Hands-On KornShell93 Programmnig' book (Barry Rosenberg - Addison Wesley). Great book, nice examples and all is clearly explained. The downside is that ksh93 isn't the same as ksh88/pdksh........
2 > &1
basically, I understand it's doing a list for the password file then write to /dev/null, but what is 2 > &1 mean?
-> all that is written to file descriptor 2 (stderr) is redirected to file descriptor 1 (stdout).
.... > /dev/null
could also be written as .... 1> /dev/null
Both forms are correct although the second example is (hopefully) easier to understand.
So this .... > /dev/null 2 >&1
will redirect both stdout (the > or 1>) and stderr (2>) to /dev/null, by means of redirecting stderr to file descriptor 1 (the &1 part).
Hope this clears things up a bit.