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32 .\" @(#)su.1 8.2 (Berkeley) 4/18/94
40 .Nd substitute user identity
46 .Op Ar login Op Ar args
49 requests appropriate user credentials via PAM
50 and switches to that user ID
51 (the default user is the superuser).
52 A shell is then executed.
54 PAM is used to set all policy.
56 By default, the environment is unmodified with the exception of
64 are set to the target login's default values.
66 is set to the target login, unless the target login has a user ID of 0,
67 in which case it is unmodified.
68 The invoked shell is the one belonging to the target login.
69 This is the traditional behavior of
71 Resource limits and session priority applicable to the original user's
74 are also normally retained unless the target login as a user ID of 0.
76 The options are as follows:
79 If the invoked shell is
81 this option prevents it from reading the
85 Simulate a full login.
86 The environment is discarded except for
96 are modified as above.
98 is set to the target login.
101 .Dq Pa /bin:/usr/bin .
103 is imported from your current environment.
104 Environment variables may be set or overridden from the login class
105 capabilities database according to the class of the target login.
106 The invoked shell is the target login's, and
108 will change directory to the target login's home directory.
109 Resource limits and session priority are modified to that for the
110 target account's login class.
112 (no letter) The same as
115 Leave the environment unmodified.
116 The invoked shell is your login shell, and no directory changes are made.
117 As a security precaution, if the target user's shell is a non-standard
120 and the caller's real uid is
125 Use the settings of the specified login class.
126 Only allowed for the super-user.
136 options are mutually exclusive; the last one specified
137 overrides any previous ones.
141 are provided on the command line, they are passed to the login shell of
144 By default (unless the prompt is reset by a startup file) the super-user
147 to remind one of its awesome power.
149 .Bl -tag -width /etc/pam.conf -compact
152 is configured with PAM support; it uses
154 entries with service name
166 Environment variables used by
170 Default home directory of real user ID unless modified as
173 Default search path of real user ID unless modified as specified above.
175 Provides terminal type which may be retained for the substituted
178 The user ID is always the effective ID (the target user ID) after an
180 unless the user ID is 0 (root).
183 .Bl -tag -width 5n -compact
184 .It Li "su man -c catman"
189 You will be asked for man's password unless your real UID is 0.
190 .It Li "su man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
191 Same as above, but the target command constitutes of more than a
192 single word and hence is quoted for use with the
194 option being passed to the shell. (Most shells expect the argument to
196 to be a single word).
197 .It Li "su -c staff man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
198 Same as above, but the target command is run with the resource limits of
201 Note: in this example, the first
205 while the second is an argument to the shell being invoked.
207 Simulate a login for user foo.
211 Simulate a login for root.