When using "su - username" to change users, zsh is not properly setting
the LOGNAME environment variable on FreeBSD. Example below.

erik@virtubsd:~% zsh --version
zsh 5.0.2 (amd64-portbld-freebsd9.1)
erik@virtubsd:~% su - root
Password:
virtubsd# echo $LOGNAME
erik
virtubsd# cat .zshrc
cat: .zshrc: No such file or directory
virtubsd# logout
erik@virtubsd:~% sudo chpass -s /bin/csh root
Password:
chpass: user information updated
erik@virtubsd:~% su - root
Password:
virtubsd# echo $LOGNAME
root
virtubsd# logout


-- 

-Erik

"For me, it is far better to grasp the universe as it really is than to
persist in delusion, however satisfying and reassuring."  --Carl Sagan