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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 has 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.
135 options are mutually exclusive; the last one specified
136 overrides any previous ones.
140 are provided on the command line, they are passed to the login shell of
143 By default (unless the prompt is reset by a startup file) the super-user
146 to remind one of its awesome power.
148 .Bl -tag -width /etc/pam.conf -compact
151 is configured with PAM support; it uses
153 entries with service name
165 Environment variables used by
169 Default home directory of real user ID unless modified as
172 Default search path of real user ID unless modified as specified above.
174 Provides terminal type which may be retained for the substituted
177 The user ID is always the effective ID (the target user ID) after an
179 unless the user ID is 0 (root).
182 .Bl -tag -width 5n -compact
183 .It Li "su man -c catman"
188 You will be asked for man's password unless your real UID is 0.
189 .It Li "su man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
190 Same as above, but the target command consists of more than a
191 single word and hence is quoted for use with the
193 option being passed to the shell. (Most shells expect the argument to
195 to be a single word).
196 .It Li "su -c staff man -c 'catman /usr/share/man /usr/local/man /usr/X11R6/man'"
197 Same as above, but the target command is run with the resource limits of
200 Note: in this example, the first
204 while the second is an argument to the shell being invoked.
206 Simulate a login for user foo.
210 Simulate a login for root.