VISUDO(1m) MAINTENANCE COMMANDS VISUDO(1m)
NNAAMMEE
visudo - edit the sudoers file
SSYYNNOOPPSSIISS
vviissuuddoo [--cchhqqssVV] [--ff _s_u_d_o_e_r_s]
DDEESSCCRRIIPPTTIIOONN
vviissuuddoo edits the _s_u_d_o_e_r_s file in a safe fashion, analogous to _v_i_p_w(1m).
vviissuuddoo locks the _s_u_d_o_e_r_s file against multiple simultaneous edits,
provides basic sanity checks, and checks for parse errors. If the
_s_u_d_o_e_r_s file is currently being edited you will receive a message to
try again later.
There is a hard-coded list of one or more editors that vviissuuddoo will use
set at compile-time that may be overridden via the _e_d_i_t_o_r _s_u_d_o_e_r_s
Default variable. This list defaults to "vi". Normally, vviissuuddoo does
not honor the VISUAL or EDITOR environment variables unless they
contain an editor in the aforementioned editors list. However, if
vviissuuddoo is configured with the _-_-_w_i_t_h_-_e_n_v_-_e_d_i_t_o_r option or the
_e_n_v___e_d_i_t_o_r Default variable is set in _s_u_d_o_e_r_s, vviissuuddoo will use any the
editor defines by VISUAL or EDITOR. Note that this can be a security
hole since it allows the user to execute any program they wish simply
by setting VISUAL or EDITOR.
vviissuuddoo parses the _s_u_d_o_e_r_s file after the edit and will not save the
changes if there is a syntax error. Upon finding an error, vviissuuddoo will
print a message stating the line number(s) where the error occurred and
the user will receive the "What now?" prompt. At this point the user
may enter "e" to re-edit the _s_u_d_o_e_r_s file, "x" to exit without saving
the changes, or "Q" to quit and save changes. The "Q" option should be
used with extreme care because if vviissuuddoo believes there to be a parse
error, so will ssuuddoo and no one will be able to ssuuddoo again until the
error is fixed. If "e" is typed to edit the _s_u_d_o_e_r_s file after a
parse error has been detected, the cursor will be placed on the line
where the error occurred (if the editor supports this feature).
OOPPTTIIOONNSS
vviissuuddoo accepts the following command line options:
-c Enable cchheecckk--oonnllyy mode. The existing _s_u_d_o_e_r_s file will be
checked for syntax and a message will be printed to the
standard output detailing the status of _s_u_d_o_e_r_s. If the
syntax check completes successfully, vviissuuddoo will exit with
a value of 0. If a syntax error is encountered, vviissuuddoo
will exit with a value of 1.
-f _s_u_d_o_e_r_s Specify and alternate _s_u_d_o_e_r_s file location. With this
option vviissuuddoo will edit (or check) the _s_u_d_o_e_r_s file of your
choice, instead of the default, _/_e_t_c_/_s_u_d_o_e_r_s. The lock
file used is the specified _s_u_d_o_e_r_s file with ".tmp"
appended to it. In cchheecckk--oonnllyy mode only, the argument to
--ff may be "-", indicating that _s_u_d_o_e_r_s will be read from
the standard input.
-h The --hh (_h_e_l_p) option causes vviissuuddoo to print a short help
message to the standard output and exit.
-q Enable qquuiieett mode. In this mode details about syntax
errors are not printed. This option is only useful when
combined with the --cc option.
-s Enable ssttrriicctt checking of the _s_u_d_o_e_r_s file. If an alias is
used before it is defined, vviissuuddoo will consider this a
parse error. Note that it is not possible to differentiate
between an alias and a host name or user name that consists
solely of uppercase letters, digits, and the underscore
('_') character.
-V The --VV (version) option causes vviissuuddoo to print its version
number and exit.
EENNVVIIRROONNMMEENNTT
The following environment variables may be consulted depending on the
value of the _e_d_i_t_o_r and _e_n_v___e_d_i_t_o_r _s_u_d_o_e_r_s variables:
VISUAL Invoked by visudo as the editor to use
EDITOR Used by visudo if VISUAL is not set
FFIILLEESS
_/_e_t_c_/_s_u_d_o_e_r_s List of who can run what
_/_e_t_c_/_s_u_d_o_e_r_s_._t_m_p Lock file for visudo
DDIIAAGGNNOOSSTTIICCSS
sudoers file busy, try again later.
Someone else is currently editing the _s_u_d_o_e_r_s file.
/etc/sudoers.tmp: Permission denied
You didn't run vviissuuddoo as root.
Can't find you in the passwd database
Your userid does not appear in the system passwd file.
Warning: {User,Runas,Host,Cmnd}_Alias referenced but not defined
Either you are trying to use an undeclare
{User,Runas,Host,Cmnd}_Alias or you have a user or host name listed
that consists solely of uppercase letters, digits, and the
underscore ('_') character. In the latter case, you can ignore the
warnings (ssuuddoo will not complain). In --ss (strict) mode these are
errors, not warnings.
Warning: unused {User,Runas,Host,Cmnd}_Alias
The specified {User,Runas,Host,Cmnd}_Alias was defined but never
used. You may wish to comment out or remove the unused alias. In
--ss (strict) mode this is an error, not a warning.
Warning: cycle in {User,Runas,Host,Cmnd}_Alias
The specified {User,Runas,Host,Cmnd}_Alias includes a reference to
itself, either directly or through an alias it includes. This is
only a warning by default as ssuuddoo will ignore cycles when parsing
the _s_u_d_o_e_r_s file.
SSEEEE AALLSSOO
_v_i(1), _s_u_d_o_e_r_s(4), _s_u_d_o(1m), _v_i_p_w(1m)
AAUUTTHHOORR
Many people have worked on _s_u_d_o over the years; this version of vviissuuddoo
was written by:
Todd Miller
See the HISTORY file in the sudo distribution or visit
http://www.sudo.ws/sudo/history.html for more details.
CCAAVVEEAATTSS
There is no easy way to prevent a user from gaining a root shell if the
editor used by vviissuuddoo allows shell escapes.
BBUUGGSS
If you feel you have found a bug in vviissuuddoo, please submit a bug report
at http://www.sudo.ws/sudo/bugs/
SSUUPPPPOORRTT
Limited free support is available via the sudo-users mailing list, see
http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
the archives.
DDIISSCCLLAAIIMMEERR
vviissuuddoo is provided ``AS IS'' and any express or implied warranties,
including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose are disclaimed.
See the LICENSE file distributed with ssuuddoo or
http://www.sudo.ws/sudo/license.html for complete details.
1.8.3 September 16, 2011 VISUDO(1m)
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