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
  44 .Op Fl flm
  45 .Op Ar login Op Ar args
  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 f
  64 If the invoked shell is
  65 .Xr csh 1 ,
  66 this option prevents it from reading the
  67 .Dq Pa .cshrc
  68 file.
  69 .It Fl l
  70 Simulate a full login.
  71 The environment is discarded except for
  72 .Ev HOME ,
  73 .Ev SHELL ,
  74 .Ev PATH ,
  75 .Ev TERM ,
  76 and
  77 .Ev USER .
  78 .Ev HOME
  79 and
  80 .Ev SHELL
  81 are modified as above.
  82 .Ev USER
  83 is set to the target login.
  84 .Ev PATH
  85 is set to
  86 .Dq Pa /bin:/usr/bin .
  87 .Ev TERM
  88 is imported from your current environment.
  89 The invoked shell is the target login's, and
  90 .Nm
  91 will change directory to the target login's home directory.
  92 This option is identical to just passing "-", as in "su -".
  93 .It Fl m
  94 Leave the environment unmodified.
  95 The invoked shell is your login shell, and no directory changes are made.
  96 As a security precaution, if the target user's shell is a non-standard
  97 shell (as defined by
  98 .Xr getusershell 3 )
  99 and the caller's real uid is
 100 non-zero,
 101 .Nm
 102 will fail.
 103 .El
 104 .Pp
 105 The
 106 .Fl l
 107 and
 108 .Fl m
 109 options are mutually exclusive; the last one specified
 110 overrides any previous ones.
 111 .Pp
 112 Only users in group
 113 .Dq wheel
 114 (normally gid 0)
 115 or group
 116 .Dq admin
 117 (normally gid 20) can
 118 .Nm
 119 to
 120 .Dq root .
 121 .Pp
 122 By default (unless the prompt is reset by a startup file) the super-user
 123 prompt is set to
 124 .Dq Sy \&#
 125 to remind one of its awesome power.
 126 .Sh SEE ALSO
 127 .Xr csh 1 ,
 128 .Xr login 1 ,
 129 .Xr sh 1 ,
 130 .Xr skey 1 ,
 131 .Xr kinit 1 ,
 132 .Xr kerberos 1 ,
 133 .Xr passwd 5 ,
 134 .Xr group 5 ,
 135 .Xr environ 7
 136 .Sh ENVIRONMENT
 137 Environment variables used by
 138 .Nm
 139 :
 140 .Bl -tag -width "HOME"
 141 .It Ev HOME
 142 Default home directory of real user ID unless modified as
 143 specified above.
 144 .It Ev PATH
 145 Default search path of real user ID unless modified as specified above.
 146 .It Ev TERM
 147 Provides terminal type which may be retained for the substituted
 148 user ID.
 149 .It Ev USER
 150 The user ID is always the effective ID (the target user ID) after an
 151 .Nm
 152 unless the user ID is 0 (root).
 153 .El
 154 .Sh HISTORY
 155 A
 156 .Nm
 157 command appeared in
 158 .At v7 .