Provided by: login_4.0.13-7ubuntu3_i386 bug


       su - change user ID or become super-user


       su [-] [username [ args ]]


       su is used to become another user during a login session. Invoked
       without a username, su defaults to becoming the super user. The
       optional argument - may be used to provide an environment similar to
       what the user would expect had the user logged in directly.

       Additional arguments may be provided after the username, in which case
       they are supplied to the userĀ“s login shell. In particular, an argument
       of -c will cause the next argument to be treated as a command by most
       command interpreters. The command will be executed by the shell
       specified in /etc/passwd for the target user.

       The user will be prompted for a password, if appropriate. Invalid
       passwords will produce an error message. All attempts, both valid and
       invalid, are logged to detect abuses of the system.

       The current environment is passed to the new shell. The value of $PATH
       is reset to /bin:/usr/bin for normal users, or
       /sbin:/bin:/usr/sbin:/usr/bin for the super user. This may be changed
       with the ENV_PATH and ENV_SUPATH definitions in /etc/login.defs.

       A subsystem login is indicated by the presence of a "*" as the first
       character of the login shell. The given home directory will be used as
       the root of a new file system which the user is actually logged into.


       This version of su has many compilation options, only some of which may
       be in use at any particular site.


              user account information

              secure user account information


       login(1), login.defs(5), sh(1), suauth(5).


       Julianne Frances Haugh <>