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SUDO(8)			     MAINTENANCE COMMANDS		       SUDO(8)

NAME
       sudo, sudoedit - execute a command as another user

SYNOPSIS
       sudo -h | -K | -k | -V

       sudo -v [-AknS] [-g group name|#gid] [-p prompt] [-u user name|#uid]

       sudo -l[l] [-AknS] [-g group name|#gid] [-p prompt] [-U user name]
       [-u user name|#uid] [command]

       sudo [-AbEHnPS] [-C fd] [-g group name|#gid] [-p prompt]
       [-u user name|#uid] [VAR=value] [-i | -s] [command]

       sudoedit [-AnS] [-C fd] [-g group name|#gid] [-p prompt]
       [-u user name|#uid] file ...

DESCRIPTION
       sudo allows a permitted user to execute a command as the superuser or
       another user, as specified by the security policy.  The real and
       effective uid and gid are set to match those of the target user, as
       specified in the password database, and the group vector is initialized
       based on the group database (unless the -P option was specified).

       sudo supports a plugin architecture for security policies and
       input/output logging.  Third parties can develop and distribute their
       own policy and I/O logging modules to work seamlessly with the sudo
       front end.  The default security policy is sudoers, which is configured
       via the file /etc/sudoers, or via LDAP.	See the PLUGINS section for
       more information.

       The security policy determines what privileges, if any, a user has to
       run sudo.  The policy may require that users authenticate themselves
       with a password or another authentication mechanism.  If authentication
       is required, sudo will exit if the user's password is not entered
       within a configurable time limit.  This limit is policy-specific; the
       default password prompt timeout for the sudoers security policy is 5
       minutes.

       Security policies may support credential caching to allow the user to
       run sudo again for a period of time without requiring authentication.
       The sudoers policy caches credentials for 5 minutes, unless overridden
       in sudoers(5).  By running sudo with the -v option, a user can update
       the cached credentials without running a command.

       When invoked as sudoedit, the -e option (described below), is implied.

       Security policies may log successful and failed attempts to use sudo.
       If an I/O plugin is configured, the running command's input and output
       may be logged as well.

OPTIONS
       sudo accepts the following command line options:

       -A	   Normally, if sudo requires a password, it will read it from
		   the user's terminal.	 If the -A (askpass) option is
		   specified, a (possibly graphical) helper program is
		   executed to read the user's password and output the
		   password to the standard output.  If the SUDO_ASKPASS
		   environment variable is set, it specifies the path to the
		   helper program.  Otherwise, if /etc/sudo.conf contains a
		   line specifying the askpass program, that value will be
		   used.  For example:

		       # Path to askpass helper program
		       Path askpass /usr/X11R6/bin/ssh-askpass

		   If no askpass program is available, sudo will exit with an
		   error.

       -b	   The -b (background) option tells sudo to run the given
		   command in the background.  Note that if you use the -b
		   option you cannot use shell job control to manipulate the
		   process.  Most interactive commands will fail to work
		   properly in background mode.

       -C fd	   Normally, sudo will close all open file descriptors other
		   than standard input, standard output and standard error.
		   The -C (close from) option allows the user to specify a
		   starting point above the standard error (file descriptor
		   three).  Values less than three are not permitted.  The
		   security policy may restrict the user's ability to use the
		   -C option.  The sudoers policy only permits use of the -C
		   option when the administrator has enabled the
		   closefrom_override option.

       -E	   The -E (preserve environment) option indicates to the
		   security policy that the user wishes to preserve their
		   existing environment variables.  The security policy may
		   return an error if the -E option is specified and the user
		   does not have permission to preserve the environment.

       -e	   The -e (edit) option indicates that, instead of running a
		   command, the user wishes to edit one or more files.	In
		   lieu of a command, the string "sudoedit" is used when
		   consulting the security policy.  If the user is authorized
		   by the policy, the following steps are taken:

		   1.  Temporary copies are made of the files to be edited
		       with the owner set to the invoking user.

		   2.  The editor specified by the policy is run to edit the
		       temporary files.	 The sudoers policy uses the
		       SUDO_EDITOR, VISUAL and EDITOR environment variables
		       (in that order).	 If none of SUDO_EDITOR, VISUAL or
		       EDITOR are set, the first program listed in the editor
		       sudoers(5) option is used.

		   3.  If they have been modified, the temporary files are
		       copied back to their original location and the
		       temporary versions are removed.

		   If the specified file does not exist, it will be created.
		   Note that unlike most commands run by sudo, the editor is
		   run with the invoking user's environment unmodified.	 If,
		   for some reason, sudo is unable to update a file with its
		   edited version, the user will receive a warning and the
		   edited copy will remain in a temporary file.

       -g group	   Normally, sudo runs a command with the primary group set to
		   the one specified by the password database for the user the
		   command is being run as (by default, root).	The -g (group)
		   option causes sudo to run the command with the primary
		   group set to group instead.	To specify a gid instead of a
		   group name, use #gid.  When running commands as a gid, many
		   shells require that the '#' be escaped with a backslash
		   ('\').  If no -u option is specified, the command will be
		   run as the invoking user (not root).	 In either case, the
		   primary group will be set to group.

       -H	   The -H (HOME) option requests that the security policy set
		   the HOME environment variable to the home directory of the
		   target user (root by default) as specified by the password
		   database.  Depending on the policy, this may be the default
		   behavior.

       -h	   The -h (help) option causes sudo to print a short help
		   message to the standard output and exit.

       -i [command]
		   The -i (simulate initial login) option runs the shell
		   specified by the password database entry of the target user
		   as a login shell.  This means that login-specific resource
		   files such as .profile or .login will be read by the shell.
		   If a command is specified, it is passed to the shell for
		   execution via the shell's -c option.	 If no command is
		   specified, an interactive shell is executed.	 sudo attempts
		   to change to that user's home directory before running the
		   shell.  The security policy shall initialize the
		   environment to a minimal set of variables, similar to what
		   is present when a user logs in.  The Command Environment
		   section in the sudoers(5) manual documents how the -i
		   option affects the environment in which a command is run
		   when the sudoers policy is in use.

       -K	   The -K (sure kill) option is like -k except that it removes
		   the user's cached credentials entirely and may not be used
		   in conjunction with a command or other option.  This option
		   does not require a password.	 Not all security policies
		   support credential caching.

       -k [command]
		   When used alone, the -k (kill) option to sudo invalidates
		   the user's cached credentials.  The next time sudo is run a
		   password will be required.  This option does not require a
		   password and was added to allow a user to revoke sudo
		   permissions from a .logout file.  Not all security policies
		   support credential caching.

		   When used in conjunction with a command or an option that
		   may require a password, the -k option will cause sudo to
		   ignore the user's cached credentials.  As a result, sudo
		   will prompt for a password (if one is required by the
		   security policy) and will not update the user's cached
		   credentials.

       -l[l] [command]
		   If no command is specified, the -l (list) option will list
		   the allowed (and forbidden) commands for the invoking user
		   (or the user specified by the -U option) on the current
		   host.  If a command is specified and is permitted by the
		   security policy, the fully-qualified path to the command is
		   displayed along with any command line arguments.  If
		   command is specified but not allowed, sudo will exit with a
		   status value of 1.  If the -l option is specified with an l
		   argument (i.e. -ll), or if -l is specified multiple times,
		   a longer list format is used.

       -n	   The -n (non-interactive) option prevents sudo from
		   prompting the user for a password.  If a password is
		   required for the command to run, sudo will display an error
		   messages and exit.

       -P	   The -P (preserve group vector) option causes sudo to
		   preserve the invoking user's group vector unaltered.	 By
		   default, the sudoers policy will initialize the group
		   vector to the list of groups the target user is in.	The
		   real and effective group IDs, however, are still set to
		   match the target user.

       -p prompt   The -p (prompt) option allows you to override the default
		   password prompt and use a custom one.  The following
		   percent (`%') escapes are supported by the sudoers policy:

		   %H  expanded to the host name including the domain name (on
		       if the machine's host name is fully qualified or the
		       fqdn option is set in sudoers(5))

		   %h  expanded to the local host name without the domain name

		   %p  expanded to the name of the user whose password is
		       being requested (respects the rootpw, targetpw and
		       runaspw flags in sudoers(5))

		   %U  expanded to the login name of the user the command will
		       be run as (defaults to root unless the -u option is
		       also specified)

		   %u  expanded to the invoking user's login name

		   %%  two consecutive % characters are collapsed into a
		       single % character

		   The prompt specified by the -p option will override the
		   system password prompt on systems that support PAM unless
		   the passprompt_override flag is disabled in sudoers.

       -S	   The -S (stdin) option causes sudo to read the password from
		   the standard input instead of the terminal device.  The
		   password must be followed by a newline character.

       -s [command]
		   The -s (shell) option runs the shell specified by the SHELL
		   environment variable if it is set or the shell as specified
		   in the password database.  If a command is specified, it is
		   passed to the shell for execution via the shell's -c
		   option.  If no command is specified, an interactive shell
		   is executed.

       -U user	   The -U (other user) option is used in conjunction with the
		   -l option to specify the user whose privileges should be
		   listed.  The security policy may restrict listing other
		   users' privileges.  The sudoers policy only allows root or
		   a user with the ALL privilege on the current host to use
		   this option.

       -u user	   The -u (user) option causes sudo to run the specified
		   command as a user other than root.  To specify a uid
		   instead of a user name, use #uid.  When running commands as
		   a uid, many shells require that the '#' be escaped with a
		   backslash ('\').  Security policies may restrict uids to
		   those listed in the password database.  The sudoers policy
		   allows uids that are not in the password database as long
		   as the targetpw option is not set.  Other security policies
		   may not support this.

       -V	   The -V (version) option causes sudo to print its version
		   string and the version string of the security policy plugin
		   and any I/O plugins.	 If the invoking user is already root
		   the -V option will display the arguments passed to
		   configure when sudo was built and plugins may display more
		   verbose information such as default options.

       -v	   When given the -v (validate) option, sudo will update the
		   user's cached credentials, authenticating the user's
		   password if necessary.  For the sudoers plugin, this
		   extends the sudo timeout for another 5 minutes (or whatever
		   the timeout is set to in sudoers) but does not run a
		   command.  Not all security policies support cached
		   credentials.

       --	   The -- option indicates that sudo should stop processing
		   command line arguments.

       Environment variables to be set for the command may also be passed on
       the command line in the form of VAR=value, e.g.
       LD_LIBRARY_PATH=/usr/local/pkg/lib.  Variables passed on the command
       line are subject to the same restrictions as normal environment
       variables with one important exception.	If the setenv option is set in
       sudoers, the command to be run has the SETENV tag set or the command
       matched is ALL, the user may set variables that would otherwise be
       forbidden.  See sudoers(5) for more information.

PLUGINS
       Plugins are dynamically loaded based on the contents of the
       /etc/sudo.conf file.  If no /etc/sudo.conf file is present, or it
       contains no Plugin lines, sudo will use the traditional sudoers
       security policy and I/O logging, which corresponds to the following
       /etc/sudo.conf file.

	#
	# Default /etc/sudo.conf file
	#
	# Format:
	#   Plugin plugin_name plugin_path
	#   Path askpass /path/to/askpass
	#   Path noexec /path/to/noexec.so
	#   Debug sudo /var/log/sudo_debug all@warn
	#   Set disable_coredump true
	#
	# The plugin_path is relative to /opt/freeware/libexec unless
	#   fully qualified.
	# The plugin_name corresponds to a global symbol in the plugin
	#   that contains the plugin interface structure.
	#
	Plugin policy_plugin sudoers.so
	Plugin io_plugin sudoers.so

       A Plugin line consists of the Plugin keyword, followed by the
       symbol_name and the path to the shared object containing the plugin.
       The symbol_name is the name of the struct policy_plugin or struct
       io_plugin in the plugin shared object.  The path may be fully qualified
       or relative.  If not fully qualified it is relative to the
       /opt/freeware/libexec directory.	 Any additional parameters after the
       path are ignored.  Lines that don't begin with Plugin or Path are
       silently ignored

       For more information, see the sudo_plugin(8) manual.

PATHS
       A Path line consists of the Path keyword, followed by the name of the
       path to set and its value.  E.g.

	Path noexec /opt/freeware/libexec/sudo_noexec.so
	Path askpass /usr/X11R6/bin/ssh-askpass

       The following plugin-agnostic paths may be set in the /etc/sudo.conf
       file.

       askpass	       The fully qualified path to a helper program used to
		       read the user's password when no terminal is available.
		       This may be the case when sudo is executed from a
		       graphical (as opposed to text-based) application.  The
		       program specified by askpass should display the
		       argument passed to it as the prompt and write the
		       user's password to the standard output.	The value of
		       askpass may be overridden by the SUDO_ASKPASS
		       environment variable.

       noexec	       The fully-qualified path to a shared library containing
		       dummy versions of the execv(), execve() and fexecve()
		       library functions that just return an error.  This is
		       used to implement the noexec functionality on systems
		       that support LD_PRELOAD or its equivalent.  Defaults to
		       /opt/freeware/libexec/sudo_noexec.so.

DEBUG FLAGS
       sudo versions 1.8.4 and higher support a flexible debugging framework
       that can help track down what sudo is doing internally if there is a
       problem.

       A Debug line consists of the Debug keyword, followed by the name of the
       program to debug (sudo, visudo, sudoreplay), the debug file name and a
       comma-separated list of debug flags.  The debug flag syntax used by
       sudo and the sudoers plugin is subsystem@priority but the plugin is
       free to use a different format so long as it does not include a command
       ,.

       For instance:

	Debug sudo /var/log/sudo_debug all@warn,plugin@info

       would log all debugging statements at the warn level and higher in
       addition to those at the info level for the plugin subsystem.

       Currently, only one Debug entry per program is supported.  The sudo
       Debug entry is shared by the sudo front end, sudoedit and the plugins.
       A future release may add support for per-plugin Debug lines and/or
       support for multiple debugging files for a single program.

       The priorities used by the sudo front end, in order of decreasing
       severity, are: crit, err, warn, notice, diag, info, trace and debug.
       Each priority, when specified, also includes all priorities higher than
       it.  For example, a priority of notice would include debug messages
       logged at notice and higher.

       The following subsystems are used by sudo:

       all	 matches every subsystem

       args	 command line argument processing

       conv	 user conversation

       edit	 sudoedit

       exec	 command execution

       main	 sudo main function

       netif	 network interface handling

       pcomm	 communication with the plugin

       plugin	 plugin configuration

       pty	 pseudo-tty related code

       selinux	 SELinux-specific handling

       util	 utility functions

       utmp	 utmp handling

RETURN VALUES
       Upon successful execution of a program, the exit status from sudo will
       simply be the exit status of the program that was executed.

       Otherwise, sudo exits with a value of 1 if there is a
       configuration/permission problem or if sudo cannot execute the given
       command.	 In the latter case the error string is printed to the
       standard error.	If sudo cannot stat(2) one or more entries in the
       user's PATH, an error is printed on stderr.  (If the directory does not
       exist or if it is not really a directory, the entry is ignored and no
       error is printed.)  This should not happen under normal circumstances.
       The most common reason for stat(2) to return "permission denied" is if
       you are running an automounter and one of the directories in your PATH
       is on a machine that is currently unreachable.

SECURITY NOTES
       sudo tries to be safe when executing external commands.

       To prevent command spoofing, sudo checks "." and "" (both denoting
       current directory) last when searching for a command in the user's PATH
       (if one or both are in the PATH).  Note, however, that the actual PATH
       environment variable is not modified and is passed unchanged to the
       program that sudo executes.

       Please note that sudo will normally only log the command it explicitly
       runs.  If a user runs a command such as sudo su or sudo sh, subsequent
       commands run from that shell are not subject to sudo's security policy.
       The same is true for commands that offer shell escapes (including most
       editors).  If I/O logging is enabled, subsequent commands will have
       their input and/or output logged, but there will not be traditional
       logs for those commands.	 Because of this, care must be taken when
       giving users access to commands via sudo to verify that the command
       does not inadvertently give the user an effective root shell.  For more
       information, please see the PREVENTING SHELL ESCAPES section in
       sudoers(5).

       To prevent the disclosure of potentially sensitive information, sudo
       disables core dumps by default while it is executing (they are re-
       enabled for the command that is run).  To aid in debugging sudo
       crashes, you may wish to re-enable core dumps by setting
       "disable_coredump" to false in the /etc/sudo.conf file.

	Set disable_coredump false

       Note that by default, most operating systems disable core dumps from
       setuid programs, which includes sudo.  To actually get a sudo core file
       you may need to enable core dumps for setuid processes.	On BSD and
       Linux systems this is accomplished via the sysctl command, on Solaris
       the coreadm command can be used.

ENVIRONMENT
       sudo utilizes the following environment variables.  The security policy
       has control over the content of the command's environment.

       EDITOR	       Default editor to use in -e (sudoedit) mode if neither
		       SUDO_EDITOR nor VISUAL is set

       MAIL	       In -i mode or when env_reset is enabled in sudoers, set
		       to the mail spool of the target user

       HOME	       Set to the home directory of the target user if -i or
		       -H are specified, env_reset or always_set_home are set
		       in sudoers, or when the -s option is specified and
		       set_home is set in sudoers

       PATH	       May be overridden by the security policy.

       SHELL	       Used to determine shell to run with -s option

       SUDO_ASKPASS    Specifies the path to a helper program used to read the
		       password if no terminal is available or if the -A
		       option is specified.

       SUDO_COMMAND    Set to the command run by sudo

       SUDO_EDITOR     Default editor to use in -e (sudoedit) mode

       SUDO_GID	       Set to the group ID of the user who invoked sudo

       SUDO_PROMPT     Used as the default password prompt

       SUDO_PS1	       If set, PS1 will be set to its value for the program
		       being run

       SUDO_UID	       Set to the user ID of the user who invoked sudo

       SUDO_USER       Set to the login of the user who invoked sudo

       USER	       Set to the target user (root unless the -u option is
		       specified)

       VISUAL	       Default editor to use in -e (sudoedit) mode if
		       SUDO_EDITOR is not set

FILES
       /etc/sudo.conf	       sudo front end configuration

EXAMPLES
       Note: the following examples assume a properly configured security
       policy.

       To get a file listing of an unreadable directory:

	$ sudo ls /usr/local/protected

       To list the home directory of user yaz on a machine where the file
       system holding ~yaz is not exported as root:

	$ sudo -u yaz ls ~yaz

       To edit the index.html file as user www:

	$ sudo -u www vi ~www/htdocs/index.html

       To view system logs only accessible to root and users in the adm group:

	$ sudo -g adm view /var/log/syslog

       To run an editor as jim with a different primary group:

	$ sudo -u jim -g audio vi ~jim/sound.txt

       To shutdown a machine:

	$ sudo shutdown -r +15 "quick reboot"

       To make a usage listing of the directories in the /home partition.
       Note that this runs the commands in a sub-shell to make the cd and file
       redirection work.

	$ sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"

SEE ALSO
       grep(1), su(1), stat(2), passwd(5), sudoers(5), sudo_plugin(8),
       sudoreplay(8), visudo(8)

AUTHORS
       Many people have worked on sudo over the years; this version consists
       of code written primarily by:

	       Todd C. Miller

       See the CONTRIBUTORS file in the sudo distribution
       (http://www.sudo.ws/sudo/contributors.html) for a list of people who
       have contributed to sudo.

HISTORY
       See the HISTORY file in the sudo distribution
       (http://www.sudo.ws/sudo/history.html) for a brief history of sudo.

CAVEATS
       There is no easy way to prevent a user from gaining a root shell if
       that user is allowed to run arbitrary commands via sudo.	 Also, many
       programs (such as editors) allow the user to run commands via shell
       escapes, thus avoiding sudo's checks.  However, on most systems it is
       possible to prevent shell escapes with the sudoers(5) module's noexec
       functionality.

       It is not meaningful to run the cd command directly via sudo, e.g.,

	$ sudo cd /usr/local/protected

       since when the command exits the parent process (your shell) will still
       be the same.  Please see the EXAMPLES section for more information.

       Running shell scripts via sudo can expose the same kernel bugs that
       make setuid shell scripts unsafe on some operating systems (if your OS
       has a /dev/fd/ directory, setuid shell scripts are generally safe).

BUGS
       If you feel you have found a bug in sudo, please submit a bug report at
       http://www.sudo.ws/sudo/bugs/

SUPPORT
       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.

DISCLAIMER
       sudo 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 sudo or
       http://www.sudo.ws/sudo/license.html for complete details.

1.8.4			       February	 5, 2012		       SUDO(8)
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