su.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)su.1	6.5	1/16/90
.TH su 1
.SH Name
su \- substitute a user ID 
.SH Syntax
.B su
[\|\fIusername\fR\|]
.PP
.B su \-
[\|\fIusername\fR\|]
.PP
.B su \-f
[\|\fIusername\fR\|]
.SH Description
.NXR "su command"
.NXR "user ID" "changing temporarily"
The 
.PN su
command requests the password of the specified
.IR username .
If the correct password is given,
.PN su
changes to that 
.I 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 
.I username.
The shell that is run is also taken from the password file entry
for 
.I username.
The new user ID stays in force until the shell exits.
.PP
If no 
.I username
is specified, `root' is assumed.
To remind the superuser of his responsibilities,
the shell substitutes `#' for its usual prompt.
.SH Options
.IP \fB\-f\fR 5
Prevents
.MS csh 1
from executing the .cshrc file, making
.PN su
start up faster.
.IP \fB\-\fR
Simulates a full login.
.SH Diagnostics
.IP "Sorry" 5n
.br
An invalid password was supplied for the specified
.IR username .
.IP "Unknown login: username" 5n
.br
The specified
.I username
was not found in the passwd database.
.IP "No directory" 5n
.br
The home directory for the
.I username
is not accessible at this time (only
with ``\-'' argument).
.IP "No shell" 5n
.br
The shell specified in the passwd database entry for
.I username
could not be executed.
.IP "Kerberos initialization failure" 5n
.br
Consult your system administrator.
.PP
If enhanced security features are enabled the following error
messages are also possible:
.PP
.IP "Requires secure terminal" 5n
.br
Attempt to su to UID 0 on a line that is not marked \fIsecure\fP in
.PN /etc/ttys .
.IP "User's password has expired" 5n
.br
Access is denied because the password for
.I username
is expired.
.IP "This account is disabled" 5n
.br
Access is denied because the auth entry corresponding to
.I username
is marked disabled.
.SH Files
.TP 17
.PN /usr/adm/sulog
Log file of anyone who became
.BR root ,
with a date mark.
.SH See Also
csh(1), sh(1), passwd(5yp), environ(7), edauth(8)
.br
\fISecurity Guide for Administrators\fP
.br
\fISecurity Guide for Users\fP