Provided by: heimdal-clients_7.5.0+dfsg-2.1_amd64 bug


     su — substitute user identity


     su [-K | --no-kerberos] [-f] [-l | --full] [-m] [-i instance | --instance=instance] [-c
        command | --command=command] [login [shell arguments]]


     su will use Kerberos authentication provided that an instance for the user wanting to change
     effective UID is present in a file named .k5login in the target user id's home directory

     A special case exists where ‘root's’ ~/.k5login needs to contain an entry for:
     ‘user/⟨instance⟩@REALM’ for su to succed (where ⟨instance⟩ is ‘root’ unless changed with

     In the absence of either an entry for current user in said file or other problems like
     missing ‘host/hostname@REALM’ keys in the system's keytab, or user typing the wrong
     password, su will fall back to traditional /etc/passwd authentication.

     When using /etc/passwd authentication, su allows ‘root’ access only to members of the group
     ‘wheel’, or to any user (with knowledge of the ‘root’ password) if that group does not
     exist, or has no members.

     The options are as follows:

     -K, --no-kerberos don't use Kerberos.

     -f don't read .cshrc.

     -l, --full simulate full login.

     -m leave environment unmodified.

     -i instance, --instance=instance root instance to use.

     -c command, --command=command command to execute.