220 lines
6.1 KiB
Groff
220 lines
6.1 KiB
Groff
.\" Copyright (c) 1988, 1990, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)su.1 8.2 (Berkeley) 4/18/94
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.\" $Id: su.1,v 1.10 1997/08/30 12:22:48 jmg Exp $
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.\"
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.\" this is for hilit19's braindeadness: "
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.Dd April 18, 1994
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.Dt SU 1
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.Os
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.Sh NAME
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.Nm su
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.Nd substitute user identity
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.Sh SYNOPSIS
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.Nm
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.Op Fl Kflm
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.Op Ar login Op Ar args
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.Sh DESCRIPTION
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.Nm Su
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requests the Kerberos password for
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.Ar login
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(or for
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.Dq Ar login Ns .root ,
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if no login is provided), and switches to
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that user and group ID after obtaining a Kerberos ticket granting ticket.
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A shell is then executed.
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.Nm Su
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will resort to the local password file to find the password for
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.Ar login
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if there is a Kerberos error.
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If
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.Nm
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is executed by root, no password is requested and a shell
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with the appropriate user ID is executed; no additional Kerberos tickets
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are obtained.
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.Pp
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By default, the environment is unmodified with the exception of
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.Ev USER ,
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.Ev HOME ,
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and
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.Ev SHELL .
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.Ev HOME
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and
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.Ev SHELL
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are set to the target login's default values.
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.Ev USER
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is set to the target login, unless the target login has a user ID of 0,
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in which case it is unmodified.
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The invoked shell is the target login's.
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This is the traditional behavior of
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.Nm su .
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Resource limits and session priority applicable to the original user's
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login class (See
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.Xr login.conf 5 )
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are also normally retained unless the target login as a user ID of 0.
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.Pp
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The options are as follows:
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.Bl -tag -width Ds
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.It Fl K
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Do not attempt to use Kerberos to authenticate the user.
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.It Fl f
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If the invoked shell is
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.Xr csh 1 ,
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this option prevents it from reading the
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.Dq Pa .cshrc
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file.
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.It Fl l
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Simulate a full login.
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The environment is discarded except for
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.Ev HOME ,
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.Ev SHELL ,
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.Ev PATH ,
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.Ev TERM ,
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and
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.Ev USER .
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.Ev HOME
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and
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.Ev SHELL
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are modified as above.
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.Ev USER
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is set to the target login.
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.Ev PATH
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is set to
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.Dq Pa /bin:/usr/bin .
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.Ev TERM
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is imported from your current environment.
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Environment variables may be set or overridden from the login class
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capabilities database according to the class of the target login.
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The invoked shell is the target login's, and
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.Nm
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will change directory to the target login's home directory.
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Resource limits and session priority are modified to that for the
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target account's login class.
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.It Fl m
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Leave the environment unmodified.
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The invoked shell is your login shell, and no directory changes are made.
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As a security precaution, if the target user's shell is a non-standard
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shell (as defined by
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.Xr getusershell 3 )
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and the caller's real uid is
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non-zero,
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.Nm
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will fail.
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.El
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.Pp
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The
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.Fl l
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and
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.Fl m
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options are mutually exclusive; the last one specified
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overrides any previous ones.
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.Pp
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If the optional
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.Ar args
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are provided on the command line, they are passed to the login shell of
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the target login. This allows it to pass arbitrary commands via
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the
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.Fl c
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option as understood by most shells. Note that
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.Fl c
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usually expects a single argument only; you have to quote it when
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passing multiple words.
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.Pp
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Only users listed in group 0 (normally
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.Dq wheel )
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can
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.Nm
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to
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.Dq root ,
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unless this group is empty.
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.Pp
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When using
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.Nm
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to become super-user, note that the invoked shell dictates the new
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command prompt and not
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.Nm su .
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Even when
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.Nm
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is invoked with the
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.Fl l
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option, the command prompt is still determined by the shell's startup
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files, specifically their manipulation of the
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.Ev PS1
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variable.
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.Sh SEE ALSO
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.Xr csh 1 ,
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.Xr kerberos 1 ,
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.Xr kinit 1 ,
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.Xr login 1 ,
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.Xr sh 1 ,
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.Xr group 5 ,
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.Xr login.conf 5 ,
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.Xr passwd 5 ,
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.Xr environ 7
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.Sh ENVIRONMENT
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Environment variables used by
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.Nm su :
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.Bl -tag -width HOME
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.It Ev HOME
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Default home directory of real user ID unless modified as
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specified above.
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.It Ev PATH
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Default search path of real user ID unless modified as specified above.
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.It Ev TERM
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Provides terminal type which may be retained for the substituted
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user ID.
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.It Ev USER
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The user ID is always the effective ID (the target user ID) after an
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.Nm
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unless the user ID is 0 (root).
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.El
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.Sh EXAMPLES
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.Bl -tag -width 5n -compact
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.It Li "su man -c catman"
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Runs the command
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.Li catman
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as user
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.Li man .
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You will be asked for man's password unless your real UID is 0.
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.It Li "su man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
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Same as above, but the target command constitutes of more than a
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single word.
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.It Li "su -l foo"
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Pretend a login for user
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.Li foo .
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.El
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.Sh HISTORY
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A
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.Nm
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command appeared in
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.At v1 .
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