su(1)su(1)Namesu - substitute a user ID
Syntaxsu [username]
su - [username]
su-f [username]
Description
The command requests the password of the specified username. If the
correct password is given, changes to that username without changing
the current directory. The user environment is unchanged except for
HOME and SHELL which are taken from the password file entry for user‐
name. The shell that is run is also taken from the password file entry
for username. The new user ID stays in force until the shell exits.
If no username is specified, `root' is assumed. To remind the supe‐
ruser of his responsibilities, the shell substitutes `#' for its usual
prompt.
Options-f Prevents from executing the .cshrc file, making start up faster.
- Simulates a full login.
Diagnostics
Sorry
An invalid password was supplied for the specified username.
Unknown login: username
The specified username was not found in the passwd database.
No directory
The home directory for the username is not accessible at this time
(only with ``-'' argument).
No shell
The shell specified in the passwd database entry for username
could not be executed.
Kerberos initialization failure
Consult your system administrator.
If enhanced security features are enabled the following error messages
are also possible:
Requires secure terminal
Attempt to su to UID 0 on a line that is not marked secure in
User's password has expired
Access is denied because the password for username is expired.
This account is disabled
Access is denied because the auth entry corresponding to username
is marked disabled.
Files
Log file of anyone who became
root, with a date mark.
See Alsocsh(1), sh(1), passwd(5yp), environ(7), edauth(8)
Security Guide for Administrators
Security Guide for Users
su(1)
