91d1372fc6
consider that SUGROUP and ROOTAUTH group contain the names of users and groups. If user is not found in the list check_ingroup() recurses on each member until either user is found or end of chain is reached. The above allows su's use of the wheel group to be extended to a large number of users without necessarily putting them in group wheel, and in a way that will work over NIS that simply extending the line length limit in getgrent.c cannot.
240 lines
6.2 KiB
Groff
240 lines
6.2 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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.\" from: @(#)su.1 8.2 (Berkeley) 4/18/94
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.\" $NetBSD: su.1,v 1.20 2001/01/10 21:33:13 sjg Exp $
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.\"
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.Dd January 14, 2000
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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 Fl c Ar login-class
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.Op Ar login Op Ar "shell arguments"
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.Sh DESCRIPTION
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.Nm
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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, and any additional
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.Ar "shell arguments"
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after the login name
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are passed to the shell.
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.Nm
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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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Alternatively, if the user enters the password "s/key", authentication
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will use the S/Key one-time password system as described in
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.Xr skey 1 .
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S/Key is a Trademark of Bellcore.
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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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.Ev SHELL ,
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and
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.Ev SU_FROM .
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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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.Ev SU_FROM
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is set to the caller's login.
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The invoked shell is the target login's.
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With the exception of
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.Ev SU_FROM
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this is the traditional behavior of
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.Nm "" .
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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 c
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Specify a login class.
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You may only override the default class if you're already root.
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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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.Ev USER ,
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and
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.Ev SU_FROM .
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.Ev HOME
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.Ev SHELL ,
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and
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.Ev SU_FROM
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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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is set to the path specified in the
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.Pa /etc/login.conf
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file (or to the default of
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.Dq Pa /usr/bin:/bin:/usr/pkg/bin:/usr/local/bin
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).
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.Ev TERM
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is imported from your current environment.
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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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.It Fl
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Same as
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.Fl l
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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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Only users in group
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.Dq wheel
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(normally gid 0),
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as listed in
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.Pa /etc/group ,
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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 group wheel does not exist or has no members.
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(If you do not want anybody to be able to
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.Nm
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to
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.Dq root ,
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make
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.Dq root
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the only member of group
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.Dq wheel ,
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which is the default.)
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.Pp
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For sites with very large user populations, group
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.Dq wheel
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can contain the names of other groups that will be considered authorized
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to
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.Nm
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to
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.Dq root .
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.Pp
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By default (unless the prompt is reset by a startup file) the super-user
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prompt is set to
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.Dq Sy \&#
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to remind one of its awesome power.
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.Sh EXAMPLES
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To become user username and use the same environment as in original shell, execute:
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.Bd -literal -offset indent
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su username
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.Ed
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To become user username and use environment as if full login would be performed,
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execute:
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.Bd -literal -offset indent
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su -l username
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.Ed
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To execute arbitrary command with privileges of user username, execute:
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.Bd -literal -offset indent
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su username -c "command args"
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.Ed
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.Sh SEE ALSO
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.Xr csh 1 ,
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.Xr login 1 ,
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.Xr sh 1 ,
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.Xr skey 1 ,
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.Xr kinit 1 ,
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.Xr kerberos 1 ,
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.Xr setusercontext 3 ,
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.Xr login.conf 5 ,
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.Xr passwd 5 ,
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.Xr group 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 "" :
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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 HISTORY
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A
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.Nm
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command appeared in
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.At v7 .
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