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.\" 34.Dd April 18, 1994 35.Dt SU 1 36.Os 37.Sh NAME 38.Nm su 39.Nd substitute user identity 40.Sh SYNOPSIS 41.Nm su 42.Op Fl Kflm 43.Op Ar login 44.Sh DESCRIPTION 45.Nm Su 46requests the Kerberos password for 47.Ar login 48(or for 49.Dq Ar login Ns .root , 50if no login is provided), and switches to 51that user and group ID after obtaining a Kerberos ticket granting ticket. 52A shell is then executed. 53.Nm Su 54will resort to the local password file to find the password for 55.Ar login 56if there is a Kerberos error. 57If 58.Nm su 59is executed by root, no password is requested and a shell 60with the appropriate user ID is executed; no additional Kerberos tickets 61are obtained. 62.Pp 63By default, the environment is unmodified with the exception of 64.Ev USER , 65.Ev HOME , 66and 67.Ev SHELL . 68.Ev HOME 69and 70.Ev SHELL 71are set to the target login's default values. 72.Ev USER 73is set to the target login, unless the target login has a user ID of 0, 74in which case it is unmodified. 75The invoked shell is the target login's. 76This is the traditional behavior of 77.Nm su . 78.Pp 79The options are as follows: 80.Bl -tag -width Ds 81.It Fl K 82Do not attempt to use Kerberos to authenticate the user. 83.It Fl f 84If the invoked shell is 85.Xr csh 1 , 86this option prevents it from reading the 87.Dq Pa .cshrc 88file. 89.It Fl l 90Simulate a full login. 91The environment is discarded except for 92.Ev HOME , 93.Ev SHELL , 94.Ev PATH , 95.Ev TERM , 96and 97.Ev USER . 98.Ev HOME 99and 100.Ev SHELL 101are modified as above. 102.Ev USER 103is set to the target login. 104.Ev PATH 105is set to 106.Dq Pa /bin:/usr/bin . 107.Ev TERM 108is imported from your current environment. 109The invoked shell is the target login's, and 110.Nm su 111will change directory to the target login's home directory. 112.It Fl m 113Leave the environment unmodified. 114The invoked shell is your login shell, and no directory changes are made. 115As a security precaution, if the target user's shell is a non-standard 116shell (as defined by 117.Xr getusershell 3 ) 118and the caller's real uid is 119non-zero, 120.Nm su 121will fail. 122.El 123.Pp 124The 125.Fl l 126and 127.Fl m 128options are mutually exclusive; the last one specified 129overrides any previous ones. 130.Pp 131Only users in group 0 (normally 132.Dq wheel ) 133can 134.Nm su 135to 136.Dq root . 137.Pp 138By default (unless the prompt is reset by a startup file) the super-user 139prompt is set to 140.Dq Sy \&# 141to remind one of its awesome power. 142.Sh SEE ALSO 143.Xr csh 1 , 144.Xr login 1 , 145.Xr sh 1 , 146.Xr kinit 1 , 147.Xr kerberos 1 , 148.Xr passwd 5 , 149.Xr group 5 , 150.Xr environ 7 151.Sh ENVIRONMENT 152Environment variables used by 153.Nm su : 154.Bl -tag -width HOME 155.It Ev HOME 156Default home directory of real user ID unless modified as 157specified above. 158.It Ev PATH 159Default search path of real user ID unless modified as specified above. 160.It Ev TERM 161Provides terminal type which may be retained for the substituted 162user ID. 163.It Ev USER 164The user ID is always the effective ID (the target user ID) after an 165.Nm su 166unless the user ID is 0 (root). 167.El 168.Sh HISTORY 169A 170.Nm 171command appeared in 172.At v7 . 173