1SUDO(8)                   BSD System Manager's Manual                  SUDO(8)
2

NAME

4     sudo, sudoedit — execute a command as another user
5

SYNOPSIS

7     sudo -h | -K | -k | -V
8     sudo -v [-ABknS] [-g group] [-h host] [-p prompt] [-u user]
9     sudo -l [-ABknS] [-g group] [-h host] [-p prompt] [-U user] [-u user]
10          [command]
11     sudo [-ABbEHnPS] [-C num] [-g group] [-h host] [-p prompt] [-r role]
12          [-t type] [-T timeout] [-u user] [VAR=value] [-i | -s] [command]
13     sudoedit [-ABknS] [-C num] [-g group] [-h host] [-p prompt] [-T timeout]
14          [-u user] file ...
15

DESCRIPTION

17     sudo allows a permitted user to execute a command as the superuser or
18     another user, as specified by the security policy.  The invoking user's
19     real (not effective) user-ID is used to determine the user name with
20     which to query the security policy.
21
22     sudo supports a plugin architecture for security policies and input/out‐
23     put logging.  Third parties can develop and distribute their own policy
24     and I/O logging plugins to work seamlessly with the sudo front end.  The
25     default security policy is sudoers, which is configured via the file
26     /etc/sudoers, or via LDAP.  See the Plugins section for more information.
27
28     The security policy determines what privileges, if any, a user has to run
29     sudo.  The policy may require that users authenticate themselves with a
30     password or another authentication mechanism.  If authentication is
31     required, sudo will exit if the user's password is not entered within a
32     configurable time limit.  This limit is policy-specific; the default
33     password prompt timeout for the sudoers security policy is 5 minutes.
34
35     Security policies may support credential caching to allow the user to run
36     sudo again for a period of time without requiring authentication.  The
37     sudoers policy caches credentials for 5 minutes, unless overridden in
38     sudoers(5).  By running sudo with the -v option, a user can update the
39     cached credentials without running a command.
40
41     When invoked as sudoedit, the -e option (described below), is implied.
42
43     Security policies may log successful and failed attempts to use sudo.  If
44     an I/O plugin is configured, the running command's input and output may
45     be logged as well.
46
47     The options are as follows:
48
49     -A, --askpass
50                 Normally, if sudo requires a password, it will read it from
51                 the user's terminal.  If the -A (askpass) option is speci‐
52                 fied, a (possibly graphical) helper program is executed to
53                 read the user's password and output the password to the stan‐
54                 dard output.  If the SUDO_ASKPASS environment variable is
55                 set, it specifies the path to the helper program.  Otherwise,
56                 if sudo.conf(5) contains a line specifying the askpass pro‐
57                 gram, that value will be used.  For example:
58
59                     # Path to askpass helper program
60                     Path askpass /usr/X11R6/bin/ssh-askpass
61
62                 If no askpass program is available, sudo will exit with an
63                 error.
64
65     -B, --bell  Ring the bell as part of the password promp when a terminal
66                 is present.  This option has no effect if an askpass program
67                 is used.
68
69     -b, --background
70                 Run the given command in the background.  Note that it is not
71                 possible to use shell job control to manipulate background
72                 processes started by sudo.  Most interactive commands will
73                 fail to work properly in background mode.
74
75     -C num, --close-from=num
76                 Close all file descriptors greater than or equal to num
77                 before executing a command.  Values less than three are not
78                 permitted.  By default, sudo will close all open file
79                 descriptors other than standard input, standard output and
80                 standard error when executing a command.  The security policy
81                 may restrict the user's ability to use this option.  The
82                 sudoers policy only permits use of the -C option when the
83                 administrator has enabled the closefrom_override option.
84
85     -E, --preserve-env
86                 Indicates to the security policy that the user wishes to pre‐
87                 serve their existing environment variables.  The security
88                 policy may return an error if the user does not have permis‐
89                 sion to preserve the environment.
90
91     --preserve-env=list
92                 Indicates to the security policy that the user wishes to add
93                 the comma-separated list of environment variables to those
94                 preserved from the user's environment.  The security policy
95                 may return an error if the user does not have permission to
96                 preserve the environment.
97
98     -e, --edit  Edit one or more files instead of running a command.  In lieu
99                 of a path name, the string "sudoedit" is used when consulting
100                 the security policy.  If the user is authorized by the pol‐
101                 icy, the following steps are taken:
102
103                 1.   Temporary copies are made of the files to be edited with
104                      the owner set to the invoking user.
105
106                 2.   The editor specified by the policy is run to edit the
107                      temporary files.  The sudoers policy uses the
108                      SUDO_EDITOR, VISUAL and EDITOR environment variables (in
109                      that order).  If none of SUDO_EDITOR, VISUAL or EDITOR
110                      are set, the first program listed in the editor
111                      sudoers(5) option is used.
112
113                 3.   If they have been modified, the temporary files are
114                      copied back to their original location and the temporary
115                      versions are removed.
116
117                 To help prevent the editing of unauthorized files, the fol‐
118                 lowing restrictions are enforced unless explicitly allowed by
119                 the security policy:
120
121                 ·  Symbolic links may not be edited (version 1.8.15 and
122                    higher).
123
124                 ·  Symbolic links along the path to be edited are not fol‐
125                    lowed when the parent directory is writable by the invok‐
126                    ing user unless that user is root (version 1.8.16 and
127                    higher).
128
129                 ·  Files located in a directory that is writable by the
130                    invoking user may not be edited unless that user is root
131                    (version 1.8.16 and higher).
132
133                 Users are never allowed to edit device special files.
134
135                 If the specified file does not exist, it will be created.
136                 Note that unlike most commands run by sudo, the editor is run
137                 with the invoking user's environment unmodified.  If, for
138                 some reason, sudo is unable to update a file with its edited
139                 version, the user will receive a warning and the edited copy
140                 will remain in a temporary file.
141
142     -g group, --group=group
143                 Run the command with the primary group set to group instead
144                 of the primary group specified by the target user's password
145                 database entry.  The group may be either a group name or a
146                 numeric group-ID (GID) prefixed with the ‘#’ character (e.g.,
147                 #0 for GID 0).  When running a command as a GID, many shells
148                 require that the ‘#’ be escaped with a backslash (‘\’).  If
149                 no -u option is specified, the command will be run as the
150                 invoking user.  In either case, the primary group will be set
151                 to group.  The sudoers policy permits any of the target
152                 user's groups to be specified via the -g option as long as
153                 the -P option is not in use.
154
155     -H, --set-home
156                 Request that the security policy set the HOME environment
157                 variable to the home directory specified by the target user's
158                 password database entry.  Depending on the policy, this may
159                 be the default behavior.
160
161     -h, --help  Display a short help message to the standard output and exit.
162
163     -h host, --host=host
164                 Run the command on the specified host if the security policy
165                 plugin supports remote commands.  Note that the sudoers plug‐
166                 in does not currently support running remote commands.  This
167                 may also be used in conjunction with the -l option to list a
168                 user's privileges for the remote host.
169
170     -i, --login
171                 Run the shell specified by the target user's password data‐
172                 base entry as a login shell.  This means that login-specific
173                 resource files such as .profile, .bash_profile or .login will
174                 be read by the shell.  If a command is specified, it is
175                 passed to the shell for execution via the shell's -c option.
176                 If no command is specified, an interactive shell is executed.
177                 sudo attempts to change to that user's home directory before
178                 running the shell.  The command is run with an environment
179                 similar to the one a user would receive at log in.  Note that
180                 most shells behave differently when a command is specified as
181                 compared to an interactive session; consult the shell's man‐
182                 ual for details.  The Command environment section in the
183                 sudoers(5) manual documents how the -i option affects the
184                 environment in which a command is run when the sudoers policy
185                 is in use.
186
187     -K, --remove-timestamp
188                 Similar to the -k option, except that it removes the user's
189                 cached credentials entirely and may not be used in conjunc‐
190                 tion with a command or other option.  This option does not
191                 require a password.  Not all security policies support cre‐
192                 dential caching.
193
194     -k, --reset-timestamp
195                 When used without a command, invalidates the user's cached
196                 credentials.  In other words, the next time sudo is run a
197                 password will be required.  This option does not require a
198                 password and was added to allow a user to revoke sudo permis‐
199                 sions from a .logout file.
200
201                 When used in conjunction with a command or an option that may
202                 require a password, this option will cause sudo to ignore the
203                 user's cached credentials.  As a result, sudo will prompt for
204                 a password (if one is required by the security policy) and
205                 will not update the user's cached credentials.
206
207                 Not all security policies support credential caching.
208
209     -l, --list  If no command is specified, list the allowed (and forbidden)
210                 commands for the invoking user (or the user specified by the
211                 -U option) on the current host.  A longer list format is used
212                 if this option is specified multiple times and the security
213                 policy supports a verbose output format.
214
215                 If a command is specified and is permitted by the security
216                 policy, the fully-qualified path to the command is displayed
217                 along with any command line arguments.  If a command is spec‐
218                 ified but not allowed by the policy, sudo will exit with a
219                 status value of 1.
220
221     -n, --non-interactive
222                 Avoid prompting the user for input of any kind.  If a pass‐
223                 word is required for the command to run, sudo will display an
224                 error message and exit.
225
226     -P, --preserve-groups
227                 Preserve the invoking user's group vector unaltered.  By
228                 default, the sudoers policy will initialize the group vector
229                 to the list of groups the target user is a member of.  The
230                 real and effective group-IDs, however, are still set to match
231                 the target user.
232
233     -p prompt, --prompt=prompt
234                 Use a custom password prompt with optional escape sequences.
235                 The following percent (‘%’) escape sequences are supported by
236                 the sudoers policy:
237
238                 %H  expanded to the host name including the domain name (on
239                     if the machine's host name is fully qualified or the fqdn
240                     option is set in sudoers(5))
241
242                 %h  expanded to the local host name without the domain name
243
244                 %p  expanded to the name of the user whose password is being
245                     requested (respects the rootpw, targetpw, and runaspw
246                     flags in sudoers(5))
247
248                 %U  expanded to the login name of the user the command will
249                     be run as (defaults to root unless the -u option is also
250                     specified)
251
252                 %u  expanded to the invoking user's login name
253
254                 %%  two consecutive ‘%’ characters are collapsed into a sin‐
255                     gle ‘%’ character
256
257                 The custom prompt will override the default prompt specified
258                 by either the security policy or the SUDO_PROMPT environment
259                 variable.  On systems that use PAM, the custom prompt will
260                 also override the prompt specified by a PAM module unless the
261                 passprompt_override flag is disabled in sudoers.
262
263     -r role, --role=role
264                 Run the command with an SELinux security context that
265                 includes the specified role.
266
267     -S, --stdin
268                 Write the prompt to the standard error and read the password
269                 from the standard input instead of using the terminal device.
270
271     -s, --shell
272                 Run the shell specified by the SHELL environment variable if
273                 it is set or the shell specified by the invoking user's pass‐
274                 word database entry.  If a command is specified, it is passed
275                 to the shell for execution via the shell's -c option.  If no
276                 command is specified, an interactive shell is executed.  Note
277                 that most shells behave differently when a command is speci‐
278                 fied as compared to an interactive session; consult the
279                 shell's manual for details.
280
281     -t type, --type=type
282                 Run the command with an SELinux security context that
283                 includes the specified type.  If no type is specified, the
284                 default type is derived from the role.
285
286     -U user, --other-user=user
287                 Used in conjunction with the -l option to list the privileges
288                 for user instead of for the invoking user.  The security pol‐
289                 icy may restrict listing other users' privileges.  The
290                 sudoers policy only allows root or a user with the ALL privi‐
291                 lege on the current host to use this option.
292
293     -T timeout, --command-timeout=timeout
294                 Used to set a timeout for the command.  If the timeout
295                 expires before the command has exited, the command will be
296                 terminated.  The security policy may restrict the ability to
297                 set command timeouts.  The sudoers policy requires that user-
298                 specified timeouts be explicitly enabled.
299
300     -u user, --user=user
301                 Run the command as a user other than the default target user
302                 (usually root).  The user may be either a user name or a
303                 numeric user-ID (UID) prefixed with the ‘#’ character (e.g.,
304                 #0 for UID 0).  When running commands as a UID, many shells
305                 require that the ‘#’ be escaped with a backslash (‘\’).  Some
306                 security policies may restrict UIDs to those listed in the
307                 password database.  The sudoers policy allows UIDs that are
308                 not in the password database as long as the targetpw option
309                 is not set.  Other security policies may not support this.
310
311     -V, --version
312                 Print the sudo version string as well as the version string
313                 of the security policy plugin and any I/O plugins.  If the
314                 invoking user is already root the -V option will display the
315                 arguments passed to configure when sudo was built and plugins
316                 may display more verbose information such as default options.
317
318     -v, --validate
319                 Update the user's cached credentials, authenticating the user
320                 if necessary.  For the sudoers plugin, this extends the sudo
321                 timeout for another 5 minutes by default, but does not run a
322                 command.  Not all security policies support cached creden‐
323                 tials.
324
325     --          The -- option indicates that sudo should stop processing com‐
326                 mand line arguments.
327
328     Environment variables to be set for the command may also be passed on the
329     command line in the form of VAR=value, e.g.,
330     LD_LIBRARY_PATH=/usr/local/pkg/lib.  Variables passed on the command line
331     are subject to restrictions imposed by the security policy plugin.  The
332     sudoers policy subjects variables passed on the command line to the same
333     restrictions as normal environment variables with one important excep‐
334     tion.  If the setenv option is set in sudoers, the command to be run has
335     the SETENV tag set or the command matched is ALL, the user may set vari‐
336     ables that would otherwise be forbidden.  See sudoers(5) for more infor‐
337     mation.
338

COMMAND EXECUTION

340     When sudo executes a command, the security policy specifies the execution
341     environment for the command.  Typically, the real and effective user and
342     group and IDs are set to match those of the target user, as specified in
343     the password database, and the group vector is initialized based on the
344     group database (unless the -P option was specified).
345
346     The following parameters may be specified by security policy:
347
348     ·  real and effective user-ID
349
350     ·  real and effective group-ID
351
352     ·  supplementary group-IDs
353
354     ·  the environment list
355
356     ·  current working directory
357
358     ·  file creation mode mask (umask)
359
360     ·  SELinux role and type
361
362     ·  scheduling priority (aka nice value)
363
364   Process model
365     There are two distinct ways sudo can run a command.
366
367     If an I/O logging plugin is configured or if the security policy explic‐
368     itly requests it, a new pseudo-terminal (“pty”) is allocated and fork(2)
369     is used to create a second sudo process, referred to as the monitor.  The
370     monitor creates a new terminal session with itself as the leader and the
371     pty as its controlling terminal, calls fork(2), sets up the execution
372     environment as described above, and then uses the execve(2) system call
373     to run the command in the child process.  The monitor exists to relay job
374     control signals between the user's existing terminal and the pty the com‐
375     mand is being run in.  This makes it possible to suspend and resume the
376     command.  Without the monitor, the command would be in what POSIX terms
377     an “orphaned process group” and it would not receive any job control sig‐
378     nals from the kernel.  When the command exits or is terminated by a sig‐
379     nal, the monitor passes the command's exit status to the main sudo
380     process and exits.  After receiving the command's exit status, the main
381     sudo passes the command's exit status to the security policy's close
382     function and exits.
383
384     If no pty is used, sudo calls fork(2), sets up the execution environment
385     as described above, and uses the execve(2) system call to run the command
386     in the child process.  The main sudo process waits until the command has
387     completed, then passes the command's exit status to the security policy's
388     close function and exits.  As a special case, if the policy plugin does
389     not define a close function, sudo will execute the command directly
390     instead of calling fork(2) first.  The sudoers policy plugin will only
391     define a close function when I/O logging is enabled, a pty is required,
392     or the pam_session or pam_setcred options are enabled.  Note that
393     pam_session and pam_setcred are enabled by default on systems using PAM.
394
395   Signal handling
396     When the command is run as a child of the sudo process, sudo will relay
397     signals it receives to the command.  The SIGINT and SIGQUIT signals are
398     only relayed when the command is being run in a new pty or when the sig‐
399     nal was sent by a user process, not the kernel.  This prevents the com‐
400     mand from receiving SIGINT twice each time the user enters control-C.
401     Some signals, such as SIGSTOP and SIGKILL, cannot be caught and thus will
402     not be relayed to the command.  As a general rule, SIGTSTP should be used
403     instead of SIGSTOP when you wish to suspend a command being run by sudo.
404
405     As a special case, sudo will not relay signals that were sent by the com‐
406     mand it is running.  This prevents the command from accidentally killing
407     itself.  On some systems, the reboot(8) command sends SIGTERM to all non-
408     system processes other than itself before rebooting the system.  This
409     prevents sudo from relaying the SIGTERM signal it received back to
410     reboot(8), which might then exit before the system was actually rebooted,
411     leaving it in a half-dead state similar to single user mode.  Note, how‐
412     ever, that this check only applies to the command run by sudo and not any
413     other processes that the command may create.  As a result, running a
414     script that calls reboot(8) or shutdown(8) via sudo may cause the system
415     to end up in this undefined state unless the reboot(8) or shutdown(8) are
416     run using the exec() family of functions instead of system() (which
417     interposes a shell between the command and the calling process).
418
419     If no I/O logging plugins are loaded and the policy plugin has not
420     defined a close() function, set a command timeout or required that the
421     command be run in a new pty, sudo may execute the command directly
422     instead of running it as a child process.
423
424   Plugins
425     Plugins may be specified via Plugin directives in the sudo.conf(5) file.
426     They may be loaded as dynamic shared objects (on systems that support
427     them), or compiled directly into the sudo binary.  If no sudo.conf(5)
428     file is present, or it contains no Plugin lines, sudo will use the tradi‐
429     tional sudoers security policy and I/O logging.  See the sudo.conf(5)
430     manual for details of the /etc/sudo.conf file and the sudo_plugin(5) man‐
431     ual for more information about the sudo plugin architecture.
432

EXIT VALUE

434     Upon successful execution of a command, the exit status from sudo will be
435     the exit status of the program that was executed.  If the command termi‐
436     nated due to receipt of a signal, sudo will send itself the same signal
437     that terminated the command.
438
439     If the -l option was specified without a command, sudo will exit with a
440     value of 0 if the user is allowed to run sudo and they authenticated suc‐
441     cessfully (as required by the security policy).  If a command is speci‐
442     fied with the -l option, the exit value will only be 0 if the command is
443     permitted by the security policy, otherwise it will be 1.
444
445     If there is an authentication failure, a configuration/permission problem
446     or if the given command cannot be executed, sudo exits with a value of 1.
447     In the latter case, the error string is printed to the standard error.
448     If sudo cannot stat(2) one or more entries in the user's PATH, an error
449     is printed to the standard error.  (If the directory does not exist or if
450     it is not really a directory, the entry is ignored and no error is
451     printed.)  This should not happen under normal circumstances.  The most
452     common reason for stat(2) to return “permission denied” is if you are
453     running an automounter and one of the directories in your PATH is on a
454     machine that is currently unreachable.
455

SECURITY NOTES

457     sudo tries to be safe when executing external commands.
458
459     To prevent command spoofing, sudo checks "." and "" (both denoting cur‐
460     rent directory) last when searching for a command in the user's PATH (if
461     one or both are in the PATH).  Note, however, that the actual PATH envi‐
462     ronment variable is not modified and is passed unchanged to the program
463     that sudo executes.
464
465     Users should never be granted sudo privileges to execute files that are
466     writable by the user or that reside in a directory that is writable by
467     the user.  If the user can modify or replace the command there is no way
468     to limit what additional commands they can run.
469
470     Please note that sudo will normally only log the command it explicitly
471     runs.  If a user runs a command such as sudo su or sudo sh, subsequent
472     commands run from that shell are not subject to sudo's security policy.
473     The same is true for commands that offer shell escapes (including most
474     editors).  If I/O logging is enabled, subsequent commands will have their
475     input and/or output logged, but there will not be traditional logs for
476     those commands.  Because of this, care must be taken when giving users
477     access to commands via sudo to verify that the command does not inadver‐
478     tently give the user an effective root shell.  For more information,
479     please see the Preventing shell escapes section in sudoers(5).
480
481     To prevent the disclosure of potentially sensitive information, sudo dis‐
482     ables core dumps by default while it is executing (they are re-enabled
483     for the command that is run).  This historical practice dates from a time
484     when most operating systems allowed set-user-ID processes to dump core by
485     default.  To aid in debugging sudo crashes, you may wish to re-enable
486     core dumps by setting “disable_coredump” to false in the sudo.conf(5)
487     file as follows:
488
489           Set disable_coredump false
490
491     See the sudo.conf(5) manual for more information.
492

ENVIRONMENT

494     sudo utilizes the following environment variables.  The security policy
495     has control over the actual content of the command's environment.
496
497     EDITOR           Default editor to use in -e (sudoedit) mode if neither
498                      SUDO_EDITOR nor VISUAL is set.
499
500     MAIL             Set to the mail spool of the target user when the -i
501                      option is specified or when env_reset is enabled in
502                      sudoers (unless MAIL is present in the env_keep list).
503
504     HOME             Set to the home directory of the target user when the -i
505                      or -H options are specified, when the -s option is spec‐
506                      ified and set_home is set in sudoers, when
507                      always_set_home is enabled in sudoers, or when env_reset
508                      is enabled in sudoers and HOME is not present in the
509                      env_keep list.
510
511     LOGNAME          Set to the login name of the target user when the -i
512                      option is specified, when the set_logname option is
513                      enabled in sudoers or when the env_reset option is
514                      enabled in sudoers (unless LOGNAME is present in the
515                      env_keep list).
516
517     PATH             May be overridden by the security policy.
518
519     SHELL            Used to determine shell to run with -s option.
520
521     SUDO_ASKPASS     Specifies the path to a helper program used to read the
522                      password if no terminal is available or if the -A option
523                      is specified.
524
525     SUDO_COMMAND     Set to the command run by sudo.
526
527     SUDO_EDITOR      Default editor to use in -e (sudoedit) mode.
528
529     SUDO_GID         Set to the group-ID of the user who invoked sudo.
530
531     SUDO_PROMPT      Used as the default password prompt unless the -p option
532                      was specified.
533
534     SUDO_PS1         If set, PS1 will be set to its value for the program
535                      being run.
536
537     SUDO_UID         Set to the user-ID of the user who invoked sudo.
538
539     SUDO_USER        Set to the login name of the user who invoked sudo.
540
541     USER             Set to the same value as LOGNAME, described above.
542
543     VISUAL           Default editor to use in -e (sudoedit) mode if
544                      SUDO_EDITOR is not set.
545

FILES

547     /etc/sudo.conf            sudo front end configuration
548

EXAMPLES

550     Note: the following examples assume a properly configured security pol‐
551     icy.
552
553     To get a file listing of an unreadable directory:
554
555           $ sudo ls /usr/local/protected
556
557     To list the home directory of user yaz on a machine where the file system
558     holding ~yaz is not exported as root:
559
560           $ sudo -u yaz ls ~yaz
561
562     To edit the index.html file as user www:
563
564           $ sudoedit -u www ~www/htdocs/index.html
565
566     To view system logs only accessible to root and users in the adm group:
567
568           $ sudo -g adm more /var/log/syslog
569
570     To run an editor as jim with a different primary group:
571
572           $ sudoedit -u jim -g audio ~jim/sound.txt
573
574     To shut down a machine:
575
576           $ sudo shutdown -r +15 "quick reboot"
577
578     To make a usage listing of the directories in the /home partition.  Note
579     that this runs the commands in a sub-shell to make the cd and file redi‐
580     rection work.
581
582           $ sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"
583

DIAGNOSTICS

585     Error messages produced by sudo include:
586
587     editing files in a writable directory is not permitted
588           By default, sudoedit does not permit editing a file when any of the
589           parent directories are writable by the invoking user.  This avoids
590           a race condition that could allow the user to overwrite an arbi‐
591           trary file.  See the sudoedit_checkdir option in sudoers(5) for
592           more information.
593
594     editing symbolic links is not permitted
595           By default, sudoedit does not follow symbolic links when opening
596           files.  See the sudoedit_follow option in sudoers(5) for more
597           information.
598
599     effective uid is not 0, is sudo installed setuid root?
600           sudo was not run with root privileges.  The sudo binary must be
601           owned by the root user and have the set-user-ID bit set.  Also, it
602           must not be located on a file system mounted with the ‘nosuid’
603           option or on an NFS file system that maps uid 0 to an unprivileged
604           uid.
605
606     effective uid is not 0, is sudo on a file system with the 'nosuid' option
607           set or an NFS file system without root privileges?
608           sudo was not run with root privileges.  The sudo binary has the
609           proper owner and permissions but it still did not run with root
610           privileges.  The most common reason for this is that the file sys‐
611           tem the sudo binary is located on is mounted with the ‘nosuid’
612           option or it is an NFS file system that maps uid 0 to an unprivi‐
613           leged uid.
614
615     fatal error, unable to load plugins
616           An error occurred while loading or initializing the plugins speci‐
617           fied in sudo.conf(5).
618
619     invalid environment variable name
620           One or more environment variable names specified via the -E option
621           contained an equal sign (‘=’).  The arguments to the -E option
622           should be environment variable names without an associated value.
623
624     no password was provided
625           When sudo tried to read the password, it did not receive any char‐
626           acters.  This may happen if no terminal is available (or the -S
627           option is specified) and the standard input has been redirected
628           from /dev/null.
629
630     a terminal is required to read the password
631           sudo needs to read the password but there is no mechanism available
632           for it to do so.  A terminal is not present to read the password
633           from, sudo has not been configured to read from the standard input,
634           the -S option was not used, and no askpass helper has been speci‐
635           fied either via the sudo.conf(5) file or the SUDO_ASKPASS environ‐
636           ment variable.
637
638     no writable temporary directory found
639           sudoedit was unable to find a usable temporary directory in which
640           to store its intermediate files.
641
642     sudo must be owned by uid 0 and have the setuid bit set
643           sudo was not run with root privileges.  The sudo binary does not
644           have the correct owner or permissions.  It must be owned by the
645           root user and have the set-user-ID bit set.
646
647     sudoedit is not supported on this platform
648           It is only possible to run sudoedit on systems that support setting
649           the effective user-ID.
650
651     timed out reading password
652           The user did not enter a password before the password timeout (5
653           minutes by default) expired.
654
655     you do not exist in the passwd database
656           Your user-ID does not appear in the system passwd database.
657
658     you may not specify environment variables in edit mode
659           It is only possible to specify environment variables when running a
660           command.  When editing a file, the editor is run with the user's
661           environment unmodified.
662

SEE ALSO

664     su(1), stat(2), login_cap(3), passwd(5), sudo.conf(5), sudo_plugin(5),
665     sudoers(5), sudoreplay(8), visudo(8)
666

HISTORY

668     See the HISTORY file in the sudo distribution (https://www.sudo.ws/his
669     tory.html) for a brief history of sudo.
670

AUTHORS

672     Many people have worked on sudo over the years; this version consists of
673     code written primarily by:
674
675           Todd C. Miller
676
677     See the CONTRIBUTORS file in the sudo distribution
678     (https://www.sudo.ws/contributors.html) for an exhaustive list of people
679     who have contributed to sudo.
680

CAVEATS

682     There is no easy way to prevent a user from gaining a root shell if that
683     user is allowed to run arbitrary commands via sudo.  Also, many programs
684     (such as editors) allow the user to run commands via shell escapes, thus
685     avoiding sudo's checks.  However, on most systems it is possible to pre‐
686     vent shell escapes with the sudoers(5) plugin's noexec functionality.
687
688     It is not meaningful to run the cd command directly via sudo, e.g.,
689
690           $ sudo cd /usr/local/protected
691
692     since when the command exits the parent process (your shell) will still
693     be the same.  Please see the EXAMPLES section for more information.
694
695     Running shell scripts via sudo can expose the same kernel bugs that make
696     set-user-ID shell scripts unsafe on some operating systems (if your OS
697     has a /dev/fd/ directory, set-user-ID shell scripts are generally safe).
698

BUGS

700     If you feel you have found a bug in sudo, please submit a bug report at
701     https://bugzilla.sudo.ws/
702

SUPPORT

704     Limited free support is available via the sudo-users mailing list, see
705     https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
706     the archives.
707

DISCLAIMER

709     sudo is provided “AS IS” and any express or implied warranties, includ‐
710     ing, but not limited to, the implied warranties of merchantability and
711     fitness for a particular purpose are disclaimed.  See the LICENSE file
712     distributed with sudo or https://www.sudo.ws/license.html for complete
713     details.
714
715Sudo 1.8.29                    October 20, 2019                    Sudo 1.8.29
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