su/su.1

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  32 .\"     from: @(#)su.1  8.2 (Berkeley) 4/18/94
  33 .\"     $NetBSD: su.1,v 1.14 1997/10/19 23:31:52 lukem Exp $
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  35 .Dd April 18, 1994
  36 .Dt SU 1
  37 .Os
  38 .Sh NAME
  39 .Nm su
  40 .Nd substitute user identity
  41 .Sh SYNOPSIS
  42 .Nm
  43 .Op Fl flm
  44 .Op Ar login
  45 .Op Ar -c shell arguments
  46 .Sh DESCRIPTION
  47 .Nm
  48 requests the password for
  49 .Ar login
  50 and switches to
  51 that user and group ID after obtaining proper authentication.
  52 A shell is then executed, and any additional
  53 .Ar "shell arguments"
  54 after the login name
  55 are passed to the shell.
  56 If
  57 .Nm
  58 is executed by root, no password is requested and a shell
  59 with the appropriate user ID is executed.
  60 .Pp
  61 The options are as follows:
  62 .Bl -tag -width Ds
  63 .It Fl c
  64 Invoke the following command in a subshell as the specified user.
  65 .It Fl f
  66 If the invoked shell is
  67 .Xr csh 1 ,
  68 this option prevents it from reading the
  69 .Dq Pa .cshrc
  70 file.
  71 .It Fl l
  72 Simulate a full login.
  73 The environment is discarded except for
  74 .Ev HOME ,
  75 .Ev SHELL ,
  76 .Ev PATH ,
  77 .Ev TERM ,
  78 and
  79 .Ev USER .
  80 .Ev HOME
  81 and
  82 .Ev SHELL
  83 are modified as above.
  84 .Ev USER
  85 is set to the target login.
  86 .Ev PATH
  87 is set to
  88 .Dq Pa /bin:/usr/bin .
  89 .Ev TERM
  90 is imported from your current environment.
  91 The invoked shell is the target login's, and
  92 .Nm
  93 will change directory to the target login's home directory.
  94 This option is identical to just passing "-", as in "su -".
  95 .It Fl m
  96 Leave the environment unmodified.
  97 The invoked shell is your login shell, and no directory changes are made.
  98 As a security precaution, if the target user's shell is a non-standard
  99 shell (as defined by
 100 .Xr getusershell 3 )
 101 and the caller's real uid is
 102 non-zero,
 103 .Nm
 104 will fail.
 105 .El
 106 .Pp
 107 The
 108 .Fl l
 109 and
 110 .Fl m
 111 options are mutually exclusive; the last one specified
 112 overrides any previous ones.
 113 .Pp
 114 Only users in group
 115 .Dq wheel
 116 (normally gid 0)
 117 or group
 118 .Dq admin
 119 (normally gid 20) can
 120 .Nm
 121 to
 122 .Dq root .
 123 .Pp
 124 By default (unless the prompt is reset by a startup file) the super-user
 125 prompt is set to
 126 .Dq Sy \&#
 127 to remind one of its awesome power.
 128 .Sh SEE ALSO
 129 .Xr csh 1 ,
 130 .Xr login 1 ,
 131 .Xr sh 1 ,
 132 .Xr skey 1 ,
 133 .Xr kinit 1 ,
 134 .Xr kerberos 1 ,
 135 .Xr passwd 5 ,
 136 .Xr group 5 ,
 137 .Xr environ 7
 138 .Sh ENVIRONMENT
 139 Environment variables used by
 140 .Nm
 141 :
 142 .Bl -tag -width "HOME"
 143 .It Ev HOME
 144 Default home directory of real user ID unless modified as
 145 specified above.
 146 .It Ev PATH
 147 Default search path of real user ID unless modified as specified above.
 148 .It Ev TERM
 149 Provides terminal type which may be retained for the substituted
 150 user ID.
 151 .It Ev USER
 152 The user ID is always the effective ID (the target user ID) after an
 153 .Nm
 154 unless the user ID is 0 (root).
 155 .El
 156 .Sh HISTORY
 157 A
 158 .Nm
 159 command appeared in
 160 .At v7 .