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32 .\" @(#)su.1 8.2 (Berkeley) 4/18/94
33 .\" $FreeBSD: src/usr.bin/su/su.1,v 1.17.2.6 2002/06/21 15:29:18 charnier Exp $
34 .\" $DragonFly: src/usr.bin/su/su.1,v 1.3 2004/05/21 05:27:12 cpressey Exp $
41 .Nd substitute user identity
47 .Op Ar login Op Ar args
51 utility requests the Kerberos password for
54 .Dq Ar login Ns .root ,
55 if no login is provided), and switches to
56 that user and group ID after obtaining a Kerberos ticket granting ticket.
57 A shell is then executed.
60 utility will resort to the local password file to find the password for
62 if there is a Kerberos error.
65 is executed by root, no password is requested and a shell
66 with the appropriate user ID is executed; no additional Kerberos tickets
69 By default, the environment is unmodified with the exception of
77 are set to the target login's default values.
79 is set to the target login, unless the target login has a user ID of 0,
80 in which case it is unmodified.
81 The invoked shell is the target login's.
82 This is the traditional behavior of
84 Resource limits and session priority applicable to the original user's
87 are also normally retained unless the target login has a user ID of 0.
89 The options are as follows:
92 Do not attempt to use Kerberos to authenticate the user.
94 If the invoked shell is
96 this option prevents it from reading the
100 Simulate a full login.
101 The environment is discarded except for
111 are modified as above.
113 is set to the target login.
116 .Dq Pa /bin:/usr/bin .
118 is imported from your current environment.
119 Environment variables may be set or overridden from the login class
120 capabilities database according to the class of the target login.
121 The invoked shell is the target login's, and
123 will change directory to the target login's home directory.
124 Resource limits and session priority are modified to that for the
125 target account's login class.
127 (no letter) The same as
130 Leave the environment unmodified.
131 The invoked shell is your login shell, and no directory changes are made.
132 As a security precaution, if the target user's shell is a non-standard
135 and the caller's real uid is
140 Use the settings of the specified login class.
141 Only allowed for the super-user.
150 options are mutually exclusive; the last one specified
151 overrides any previous ones.
155 are provided on the command line, they are passed to the login shell of
158 Only users who are a member of group 0 (normally
164 \ If group 0 is missing or empty, any user can
169 By default (unless the prompt is reset by a startup file) the super-user
172 to remind one of its awesome power.
174 .Bl -tag -width /etc/auth.conf -compact
175 .It Pa /etc/auth.conf
176 configure authentication services
190 Environment variables used by
194 Default home directory of real user ID unless modified as
197 Default search path of real user ID unless modified as specified above.
199 Provides terminal type which may be retained for the substituted
202 The user ID is always the effective ID (the target user ID) after an
204 unless the user ID is 0 (root).
207 .Bl -tag -width 5n -compact
208 .It Li "su man -c catman"
213 assuming man's shell supports the
216 You will be asked for man's password unless your real UID is 0.
217 .It Li "su -m man -c catman"
218 Same as above, but use the shell and environment of the current
219 user instead of those of man.
220 This allows commands to be executed as user man even when man's shell is
222 .It Li "su -mf man -c catman"
223 Same as above, but do not re-evaluate the current user's
226 .It Li "su -mf man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
227 Same as above, but the target command consists of more than a
228 single word and hence is quoted for use with the
230 option being passed to the shell. (Most shells expect the argument to
232 to be a single word).
233 .It Li "su -mf -c staff man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
234 Same as above, but the target command is run with the resource limits of
237 Note: in this example, the first
241 while the second is an argument to the shell being invoked.
243 Simulate a login for user foo.
247 Simulate a login for root.