NAME

su - substitute user id temporarily (includes AFS and NFS extensions)

SYNOPSIS

su[ -f] [ -] [ userid ]

DESCRIPTION

Su demands the password of the specified userid, and if it is given, changes to that userid and invokes sh(1) without changing the current directory.  The user environment is unchanged except for HOME and SHELL, which are taken from the password file for the user being substituted. The new user id stays in force until the shell exits by entering “exit" in the C-shell or “ctrl-D" in the Bourne shell. 

If no userid is specified, "root" is assumed.  To remind the super-user of his or her responsibilities, the Shell substitutes ‘#’ for its usual prompt. 

The -f option prevents csh(1) from executing the .cshrc file allowing su to start up faster. 

The - option simulates a full login (sources .cshrc and .login). 

If the system is running Andrew File System authentication su attempts to validate the user’s password with the Andrew file system file servers. If successful, su informs the local Andrew Cache Manager process of the password so that it can make file server requests on the user’s behalf.  If the password typed does not match  the password in the Andrew file system but does match the password in /etc/passwd (or yellow pages), then su will allow a "local su."  The user can use the machine but will only have anonymous user access to remote files.  The user "root" always gets a local su. 

Login initializes the environment variable, environ (7), with information specifying home directory and command interpreter.  By default login sets the environment variable AUTH to UNIX preventing the user from logging in to another machine with rlogin.  To receive authentication on the remote host either use the -v option with rlogin, rsh, or rcp or set AUTH to "viceii" by issuing the command:

setenv AUTH=viceii

on the command line.  AUTH can also be permanently changed in the .login file. 

SEE ALSO

sh(1)

NOTES

Local administrative rules cause restrictions to be placed on who can su to "root", even with the root password.  These rules vary from site to site. 

Most end users should be wary of sharing passwords through protected files as is possible with su since it can lead to compromised security for the user IDs involved.  This page intentionally left blank. 

PRPQs 5799-WZQ/5799-PFF: IBM/4.3  —  Sept 1988