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 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 fB$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 presense of a "*" as the first character of the login shell. The given home directory will be used as the root of a new filesystem which the user is actually logged into.

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

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

AUTHOR
Julianne Frances Haugh <jockgrrl@ix.netcom.com>