1.\" Copyright (c) 1988, 1990, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)su.1 8.2 (Berkeley) 4/18/94 33.\" $Id: su.1,v 1.14 1998/06/08 05:29:51 jkoshy Exp $ 34.\" 35.\" this is for hilit19's braindeadness: " 36.Dd April 18, 1994 37.Dt SU 1 38.Os 39.Sh NAME 40.Nm su 41.Nd substitute user identity 42.Sh SYNOPSIS 43.Nm 44.Op Fl Kflm 45.Op Fl c Ar class 46.Op Ar login Op Ar args 47.Sh DESCRIPTION 48.Nm Su 49requests the Kerberos password for 50.Ar login 51(or for 52.Dq Ar login Ns .root , 53if no login is provided), and switches to 54that user and group ID after obtaining a Kerberos ticket granting ticket. 55A shell is then executed. 56.Nm Su 57will resort to the local password file to find the password for 58.Ar login 59if there is a Kerberos error. 60If 61.Nm 62is executed by root, no password is requested and a shell 63with the appropriate user ID is executed; no additional Kerberos tickets 64are obtained. 65.Pp 66By default, the environment is unmodified with the exception of 67.Ev USER , 68.Ev HOME , 69and 70.Ev SHELL . 71.Ev HOME 72and 73.Ev SHELL 74are set to the target login's default values. 75.Ev USER 76is set to the target login, unless the target login has a user ID of 0, 77in which case it is unmodified. 78The invoked shell is the target login's. 79This is the traditional behavior of 80.Nm su . 81Resource limits and session priority applicable to the original user's 82login class (See 83.Xr login.conf 5 ) 84are also normally retained unless the target login as a user ID of 0. 85.Pp 86The options are as follows: 87.Bl -tag -width Ds 88.It Fl K 89Do not attempt to use Kerberos to authenticate the user. 90.It Fl f 91If the invoked shell is 92.Xr csh 1 , 93this option prevents it from reading the 94.Dq Pa .cshrc 95file. 96.It Fl l 97Simulate a full login. 98The environment is discarded except for 99.Ev HOME , 100.Ev SHELL , 101.Ev PATH , 102.Ev TERM , 103and 104.Ev USER . 105.Ev HOME 106and 107.Ev SHELL 108are modified as above. 109.Ev USER 110is set to the target login. 111.Ev PATH 112is set to 113.Dq Pa /bin:/usr/bin . 114.Ev TERM 115is imported from your current environment. 116Environment variables may be set or overridden from the login class 117capabilities database according to the class of the target login. 118The invoked shell is the target login's, and 119.Nm 120will change directory to the target login's home directory. 121Resource limits and session priority are modified to that for the 122target account's login class. 123.It Fl m 124Leave the environment unmodified. 125The invoked shell is your login shell, and no directory changes are made. 126As a security precaution, if the target user's shell is a non-standard 127shell (as defined by 128.Xr getusershell 3 ) 129and the caller's real uid is 130non-zero, 131.Nm 132will fail. 133.It Fl c Ar class 134Use the settings of the specified login class. Only allowed for the super-user. 135.El 136.Pp 137The 138.Fl l 139and 140.Fl m 141options are mutually exclusive; the last one specified 142overrides any previous ones. 143.Pp 144If the optional 145.Ar args 146are provided on the command line, they are passed to the login shell of 147the target login. 148.Pp 149Only users who are a member of group 0 (normally 150.Dq wheel ) 151can 152.Nm 153to 154.Dq root . 155\ If group 0 is missing or empty, any user can 156.Nm 157to 158.Dq root . 159.Pp 160By default (unless the prompt is reset by a startup file) the super-user 161prompt is set to 162.Dq Sy \&# 163to remind one of its awesome power. 164.Sh FILES 165.Bl -tag -width /etc/auth.conf -compact 166.It Pa /etc/auth.conf 167configure authentication services 168.El 169.Sh SEE ALSO 170.Xr csh 1 , 171.Xr kerberos 1 , 172.Xr kinit 1 , 173.Xr login 1 , 174.Xr sh 1 , 175.Xr group 5 , 176.Xr login.conf 5 , 177.Xr passwd 5 , 178.Xr environ 7 179.Sh ENVIRONMENT 180Environment variables used by 181.Nm su : 182.Bl -tag -width HOME 183.It Ev HOME 184Default home directory of real user ID unless modified as 185specified above. 186.It Ev PATH 187Default search path of real user ID unless modified as specified above. 188.It Ev TERM 189Provides terminal type which may be retained for the substituted 190user ID. 191.It Ev USER 192The user ID is always the effective ID (the target user ID) after an 193.Nm 194unless the user ID is 0 (root). 195.El 196.Sh EXAMPLES 197.Bl -tag -width 5n -compact 198.It Li "su man -c catman" 199Runs the command 200.Li catman 201as user 202.Li man . 203You will be asked for man's password unless your real UID is 0. 204.It Li "su man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'" 205Same as above, but the target command constitutes of more than a 206single word and hence is quoted for use with the 207.Fl c 208option being passed to the shell. (Most shells expect the argument to 209.Fl c 210to be a single word). 211.It Li "su -c staff man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'" 212Same as above, but the target command is run with the resource limits of 213the login class 214.Dq staff . 215Note: in this example, the first 216.Fl c 217option applies to 218.Nm 219while the second is an argument to the shell being invoked. 220.It Li "su -l foo" 221Pretend a login for user 222.Li foo . 223.El 224.Sh HISTORY 225A 226.Nm 227command appeared in 228.At v1 . 229