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.\" $FreeBSD$ 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 45.Op Fl flm 46.Op Fl c Ar class 47.Op Ar login Op Ar args 48.Sh DESCRIPTION 49.Nm Su 50requests the superuser password for 51.Ar login 52(or if Kerberos PAMs are used for 53.Dq Ar login Ns .root 54or 55.Dq Ar login Ns /root 56as appropriate), 57and switches to that user ID. 58A shell is then executed. 59.Nm Su 60will resort to the local password file to find the password for 61.Ar login 62if there is a PAM error. 63If 64.Nm 65is executed by root, no password is requested and a shell 66with the appropriate user ID is executed; 67no additional PAM work is done. 68.Pp 69By default, the environment is unmodified with the exception of 70.Ev USER , 71.Ev HOME , 72and 73.Ev SHELL . 74.Ev HOME 75and 76.Ev SHELL 77are set to the target login's default values. 78.Ev USER 79is set to the target login, unless the target login has a user ID of 0, 80in which case it is unmodified. 81The invoked shell is the one belonging to the target login. 82This is the traditional behavior of 83.Nm . 84Resource limits and session priority applicable to the original user's 85login class (See 86.Xr login.conf 5 ) 87are also normally retained unless the target login as a user ID of 0. 88.Pp 89The options are as follows: 90.Bl -tag -width Ds 91.It Fl f 92If the invoked shell is 93.Xr csh 1 , 94this option prevents it from reading the 95.Dq Pa .cshrc 96file. 97.It Fl l 98Simulate a full login. 99The environment is discarded except for 100.Ev HOME , 101.Ev SHELL , 102.Ev PATH , 103.Ev TERM , 104and 105.Ev USER . 106.Ev HOME 107and 108.Ev SHELL 109are modified as above. 110.Ev USER 111is set to the target login. 112.Ev PATH 113is set to 114.Dq Pa /bin:/usr/bin . 115.Ev TERM 116is imported from your current environment. 117Environment variables may be set or overridden from the login class 118capabilities database according to the class of the target login. 119The invoked shell is the target login's, and 120.Nm 121will change directory to the target login's home directory. 122Resource limits and session priority are modified to that for the 123target account's login class. 124.It Fl 125(no letter) The same as 126.Fl l . 127.It Fl m 128Leave the environment unmodified. 129The invoked shell is your login shell, and no directory changes are made. 130As a security precaution, if the target user's shell is a non-standard 131shell (as defined by 132.Xr getusershell 3 ) 133and the caller's real uid is 134non-zero, 135.Nm 136will fail. 137.It Fl c Ar class 138Use the settings of the specified login class. 139Only allowed for the super-user. 140.El 141.Pp 142The 143.Fl l 144(or 145.Fl 146) 147and 148.Fl m 149options are mutually exclusive; the last one specified 150overrides any previous ones. 151.Pp 152If the optional 153.Ar args 154are provided on the command line, they are passed to the login shell of 155the target login. 156.Pp 157Only users who are a member of group 0 (normally 158.Dq wheel ) 159can 160.Nm 161to 162.Dq root . 163\ If group 0 is missing or empty, any user can 164.Nm 165to 166.Dq root . 167.Pp 168By default (unless the prompt is reset by a startup file) the super-user 169prompt is set to 170.Dq Sy \&# 171to remind one of its awesome power. 172.Sh FILES 173.Bl -tag -width /etc/auth.conf -compact 174.It Pa /etc/auth.conf 175configure authentication services 176.It Pa /etc/pam.conf 177if 178.Nm 179is configured with PAM support, it uses 180.Pa /etc/pam.conf 181entries with service name 182.Dq su 183.El 184.Sh SEE ALSO 185.Xr csh 1 , 186.Xr kerberos 1 , 187.Xr kinit 1 , 188.Xr login 1 , 189.Xr sh 1 , 190.Xr group 5 , 191.Xr login.conf 5 , 192.Xr passwd 5 , 193.Xr environ 7 , 194.Xr pam 8 195.Sh ENVIRONMENT 196Environment variables used by 197.Nm : 198.Bl -tag -width HOME 199.It Ev HOME 200Default home directory of real user ID unless modified as 201specified above. 202.It Ev PATH 203Default search path of real user ID unless modified as specified above. 204.It Ev TERM 205Provides terminal type which may be retained for the substituted 206user ID. 207.It Ev USER 208The user ID is always the effective ID (the target user ID) after an 209.Nm 210unless the user ID is 0 (root). 211.El 212.Sh EXAMPLES 213.Bl -tag -width 5n -compact 214.It Li "su man -c catman" 215Runs the command 216.Li catman 217as user 218.Li man . 219You will be asked for man's password unless your real UID is 0. 220.It Li "su man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'" 221Same as above, but the target command constitutes of more than a 222single word and hence is quoted for use with the 223.Fl c 224option being passed to the shell. (Most shells expect the argument to 225.Fl c 226to be a single word). 227.It Li "su -c staff man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'" 228Same as above, but the target command is run with the resource limits of 229the login class 230.Dq staff . 231Note: in this example, the first 232.Fl c 233option applies to 234.Nm 235while the second is an argument to the shell being invoked. 236.It Li "su -l foo" 237Simulate a login for user foo. 238.It Li "su - foo" 239Same as above. 240.It Li "su - " 241Simulate a login for root. 242.El 243.Sh HISTORY 244A 245.Nm 246command appeared in 247.At v1 . 248