find user name with shadow passwd 

$ grep szabo /etc/passwd
+kszabo:::::/home/users/kszabo:/bin/csh
$ ypmatch kszabo passwd
kszabo:Q4QuCgWLhW/Xo:18226:2323:Kevin Szabo:/users/guest:/bin/csh

documented on: 2000.04.25 Tue 18:03:13