SU(1)

NAME
su - Change user ID or become super-user

SYNOPSIS
su [ - ] [ username [ args ] ]

DESCRIPTION
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 similiar 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 user'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 under the shell specified by $SHELL, or if undefined, by the one specified in /etc/passwd.

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 /bin:/usr/bin:/etc for the super user.

CAVEATS

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

Files
/etc/passwd - user account information
/etc/shadow - encrypted passwords and age information
$HOME/.profile - initialization script for default shell

See Also
login(1), sh(1)