Usage: su [-Kflmh] [--no-kerberos] [--full] [--instance=string] [-i string] [--command=string]
   [-c string] [--help] [--version] [login [shell arguments]]
-K, --no-kerberos            don't use kerberos
-f                           don't read .cshrc
-l, --full                   simulate full login
-m                           leave environment unmodified
-i string, --instance=string root instance to use
-c string, --command=string  command to execute