.\" DO NOT EDIT THIS FILE, IT IS NOT THE MASTER!
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.\" Copyright (c) 1994-1996, 1998-2005, 2007-2013
.\"	Todd C. Miller <Todd.Miller@courtesan.com>
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.TH "SUDO" "@mansectsu@" "March 13, 2013" "Sudo @PACKAGE_VERSION@" "System Manager's Manual"
.nh
.if n .ad l
.SH "NAME"
\fBsudo\fR,
\fBsudoedit\fR
\- execute a command as another user
.SH "SYNOPSIS"
.HP 5n
\fBsudo\fR
\fB\-h\fR | \fB\-K\fR | \fB\-k\fR | \fB\-V\fR
.PD 0
.HP 5n
\fBsudo\fR
\fB\-v\fR
[\fB\-AknS\fR]
[\fB\-a\fR\ \fIauth_type\fR]
[\fB\-g\fR\ \fIgroup\ name\fR\ |\ \fI#gid\fR]
[\fB\-p\fR\ \fIprompt\fR]
[\fB\-u\fR\ \fIuser\ name\fR\ |\ \fI#uid\fR]
.br
.HP 5n
\fBsudo\fR
\fB\-l\fR[\fIl\fR]
[\fB\-AknS\fR]
[\fB\-a\fR\ \fIauth_type\fR]
[\fB\-g\fR\ \fIgroup\ name\fR\ |\ \fI#gid\fR]
[\fB\-p\fR\ \fIprompt\fR]
[\fB\-U\fR\ \fIuser\ name\fR]
[\fB\-u\fR\ \fIuser\ name\fR\ |\ \fI#uid\fR]
[\fIcommand\fR]
.br
.HP 5n
\fBsudo\fR
[\fB\-AbEHnPS\fR]
[\fB\-a\fR\ \fIauth_type\fR]
[\fB\-C\fR\ \fIfd\fR]
[\fB\-c\fR\ \fIclass\fR\ |\ \fI-\fR]
[\fB\-g\fR\ \fIgroup\ name\fR\ |\ \fI#gid\fR]
[\fB\-p\fR\ \fIprompt\fR]
[\fB\-r\fR\ \fIrole\fR]
[\fB\-t\fR\ \fItype\fR]
[\fB\-u\fR\ \fIuser\ name\fR\ |\ \fI#uid\fR]
[\fBVAR\fR=\fIvalue\fR]
\fB\-i\fR\ |\ \fB\-s\fR
[\fIcommand\fR]
.br
.HP 9n
\fBsudoedit\fR
[\fB\-AnS\fR]
[\fB\-a\fR\ \fIauth_type\fR]
[\fB\-C\fR\ \fIfd\fR]
[\fB\-c\fR\ \fIclass\fR\ |\ \fI-\fR]
[\fB\-g\fR\ \fIgroup\ name\fR\ |\ \fI#gid\fR]
[\fB\-p\fR\ \fIprompt\fR]
[\fB\-u\fR\ \fIuser\ name\fR\ |\ \fI#uid\fR]
file ...
.PD
.SH "DESCRIPTION"
\fBsudo\fR
allows a permitted user to execute a
\fIcommand\fR
as the superuser or another user, as specified by the security
policy.
.PP
\fBsudo\fR
supports a plugin architecture for security policies and input/output
logging.
Third parties can develop and distribute their own policy and I/O
logging plugins to work seamlessly with the
\fBsudo\fR
front end.
The default security policy is
\fIsudoers\fR,
which is configured via the file
\fI@sysconfdir@/sudoers\fR,
or via LDAP.
See the
\fIPlugins\fR
section for more information.
.PP
The security policy determines what privileges, if any, a user has
to run
\fBsudo\fR.
The policy may require that users authenticate themselves with a
password or another authentication mechanism.
If authentication is required,
\fBsudo\fR
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
\fIsudoers\fR
security policy is
\fR@password_timeout@\fR
minutes.
.PP
Security policies may support credential caching to allow the user
to run
\fBsudo\fR
again for a period of time without requiring authentication.
The
\fIsudoers\fR
policy caches credentials for
\fR@timeout@\fR
minutes, unless overridden in
sudoers(@mansectform@).
By running
\fBsudo\fR
with the
\fB\-v\fR
option, a user can update the cached credentials without running a
\fIcommand\fR.
.PP
When invoked as
\fBsudoedit\fR,
the
\fB\-e\fR
option (described below), is implied.
.PP
Security policies may log successful and failed attempts to use
\fBsudo\fR.
If an I/O plugin is configured, the running command's input and
output may be logged as well.
.PP
The options are as follows:
.TP 12n
\fB\-A\fR
Normally, if
\fBsudo\fR
requires a password, it will read it from the user's terminal.
If the
\fB\-A\fR (\fIaskpass\fR)
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
\fRSUDO_ASKPASS\fR
environment variable is set, it specifies the path to the helper
program.
Otherwise, if
sudo.conf(@mansectform@)
contains a line specifying the askpass program, that value will be
used.
For example:
.RS
.nf
.sp
.RS 4n
# Path to askpass helper program
Path askpass /usr/X11R6/bin/ssh-askpass
.RE
.fi
.sp
If no askpass program is available,
\fBsudo\fR
will exit with an error.
.PP
.RE
.PD 0
.TP 12n
\fB\-a\fR \fItype\fR
The
\fB\-a\fR (\fIauthentication type\fR)
option causes
\fBsudo\fR
to use the specified authentication type when validating the user,
as allowed by
\fI/etc/login.conf\fR.
The system administrator may specify a list of sudo-specific
authentication methods by adding an
``auth-sudo''
entry in
\fI/etc/login.conf\fR.
This option is only available on systems that support BSD authentication.
.PD
.TP 12n
\fB\-b\fR
The
\fB\-b\fR (\fIbackground\fR)
option tells
\fBsudo\fR
to run the given command in the background.
Note that if you use the
\fB\-b\fR
option you cannot use shell job control to manipulate the process.
Most interactive commands will fail to work properly in background
mode.
.TP 12n
\fB\-C\fR \fIfd\fR
Normally,
\fBsudo\fR
will close all open file descriptors other than standard input,
standard output and standard error.
The
\fB\-C\fR (\fIclose from\fR)
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
\fB\-C\fR
option.
The
\fIsudoers\fR
policy only permits use of the
\fB\-C\fR
option when the administrator has enabled the
\fIclosefrom_override\fR
option.
.TP 12n
\fB\-c\fR \fIclass\fR
The
\fB\-c\fR (\fIclass\fR)
option causes
\fBsudo\fR
to run the specified command with resources limited by the specified
login class.
The
\fIclass\fR
argument can be either a class name as defined in
\fI/etc/login.conf\fR,
or a single
`\-'
character.
Specifying a
\fIclass\fR
of
\fR-\fR
indicates that the command should be run restricted by the default
login capabilities for the user the command is run as.
If the
\fIclass\fR
argument specifies an existing user class, the command must be run
as root, or the
\fBsudo\fR
command must be run from a shell that is already root.
This option is only available on systems with BSD login classes.
.TP 12n
\fB\-E\fR
The
\fB\-E\fR (\fIpreserve environment\fR)
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
\fB\-E\fR
option is specified and the user does not have permission to preserve
the environment.
.TP 12n
\fB\-e\fR
The
\fB\-e\fR (\fIedit\fR)
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:
.RS
.TP 5n
1.
Temporary copies are made of the files to be edited with the owner
set to the invoking user.
.TP 5n
2.
The editor specified by the policy is run to edit the temporary
files.
The
\fIsudoers\fR
policy uses the
\fRSUDO_EDITOR\fR,
\fRVISUAL\fR
and
\fREDITOR\fR
environment variables (in that order).
If none of
\fRSUDO_EDITOR\fR,
\fRVISUAL\fR
or
\fREDITOR\fR
are set, the first program listed in the
\fIeditor\fR
sudoers(@mansectform@)
option is used.
.TP 5n
3.
If they have been modified, the temporary files are copied back to
their original location and the temporary versions are removed.
.PP
If the specified file does not exist, it will be created.
Note that unlike most commands run by
\fIsudo\fR,
the editor is run with the invoking user's environment unmodified.
If, for some reason,
\fBsudo\fR
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.
.PP
.RE
.PD 0
.TP 12n
\fB\-g\fR \fIgroup\fR
Normally,
\fBsudo\fR
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
\fB\-g\fR (\fIgroup\fR)
option causes
\fBsudo\fR
to run the command with the primary group set to
\fIgroup\fR
instead.
To specify a
\fIgid\fR
instead of a
\fIgroup name\fR,
use
\fI#gid\fR.
When running commands as a
\fIgid\fR,
many shells require that the
`#'
be escaped with a backslash
(`\e').
If no
\fB\-u\fR
option is specified, the command will be run as the invoking user
(not root).
In either case, the primary group will be set to
\fIgroup\fR.
.PD
.TP 12n
\fB\-H\fR
The
\fB\-H\fR (\fIHOME\fR)
option requests that the security policy set the
\fRHOME\fR
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.
.TP 12n
\fB\-h\fR
The
\fB\-h\fR (\fIhelp\fR)
option causes
\fBsudo\fR
to print a short help message to the standard output and exit.
.TP 12n
\fB\-i\fR [\fIcommand\fR]
The
\fB\-i\fR (\fIsimulate initial login\fR)
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
\fI.profile\fR
or
\fI.login\fR
will be read by the shell.
If a command is specified, it is passed to the shell for execution
via the shell's
\fB\-c\fR
option.
If no command is specified, an interactive shell is executed.
\fBsudo\fR
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
\fICommand Environment\fR
section in the
sudoers(@mansectform@)
manual documents how the
\fB\-i\fR
option affects the environment in which a command is run when the
\fIsudoers\fR
policy is in use.
.TP 12n
\fB\-K\fR
The
\fB\-K\fR (sure \fIkill\fR)
option is like
\fB\-k\fR
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.
.TP 12n
\fB\-k\fR [\fIcommand\fR]
When used alone, the
\fB\-k\fR (\fIkill\fR)
option to
\fBsudo\fR
invalidates the user's cached credentials.
The next time
\fBsudo\fR
is run a password will be required.
This option does not require a password and was added to allow a
user to revoke
\fBsudo\fR
permissions from a
\fI.logout\fR
file.
Not all security policies support credential caching.
.sp
When used in conjunction with a command or an option that may require
a password, the
\fB\-k\fR
option will cause
\fBsudo\fR
to ignore the user's cached credentials.
As a result,
\fBsudo\fR
will prompt for a password (if one is required by the security
policy) and will not update the user's cached credentials.
.TP 12n
\fB\-l\fR[\fBl\fR] [\fIcommand\fR]
If no
\fIcommand\fR
is specified, the
\fB\-l\fR (\fIlist\fR)
option will list the allowed (and forbidden) commands for the
invoking user (or the user specified by the
\fB\-U\fR
option) on the current host.
If a
\fIcommand\fR
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
\fIcommand\fR
is specified but not allowed,
\fBsudo\fR
will exit with a status value of 1.
If the
\fB\-l\fR
option is specified with an
\fIl\fR
argument
(i.e.\& \fB\-ll\fR),
or if
\fB\-l\fR
is specified multiple times, a longer list format is used.
.TP 12n
\fB\-n\fR
The
\fB\-n\fR (\fInon-interactive\fR)
option prevents
\fBsudo\fR
from prompting the user for a password.
If a password is required for the command to run,
\fBsudo\fR
will display an error message and exit.
.TP 12n
\fB\-P\fR
The
\fB\-P\fR (\fIpreserve group vector\fR)
option causes
\fBsudo\fR
to preserve the invoking user's group vector unaltered.
By default, the
\fIsudoers\fR
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.
.TP 12n
\fB\-p\fR \fIprompt\fR
The
\fB\-p\fR (\fIprompt\fR)
option allows you to override the default password prompt and use
a custom one.
The following percent
(`%')
escapes are supported by the
\fIsudoers\fR
policy:
.RS
.TP 4n
\fR%H\fR
expanded to the host name including the domain name (on if the
machine's host name is fully qualified or the
\fIfqdn\fR
option is set in
sudoers(@mansectform@))
.TP 4n
\fR%h\fR
expanded to the local host name without the domain name
.TP 4n
\fR%p\fR
expanded to the name of the user whose password is being requested
(respects the
\fIrootpw\fR,
\fItargetpw\fR,
and
\fIrunaspw\fR
flags in
sudoers(@mansectform@))
.TP 4n
\fR\&%U\fR
expanded to the login name of the user the command will be run as
(defaults to root unless the
\fB\-u\fR
option is also specified)
.TP 4n
\fR%u\fR
expanded to the invoking user's login name
.TP 4n
\fR%%\fR
two consecutive
`%'
characters are collapsed into a single
`%'
character
.PP
The prompt specified by the
\fB\-p\fR
option will override the system password prompt on systems that
support PAM unless the
\fIpassprompt_override\fR
flag is disabled in
\fIsudoers\fR.
.PP
.RE
.PD 0
.TP 12n
\fB\-r\fR \fIrole\fR
The
\fB\-r\fR (\fIrole\fR)
option causes the new (SELinux) security context to have the role
specified by
\fIrole\fR.
.PD
.TP 12n
\fB\-S\fR
The
\fB\-S\fR (\fIstdin\fR)
option causes
\fBsudo\fR
to read the password from the standard input instead of the terminal
device.
The password must be followed by a newline character.
.TP 12n
\fB\-s\fR [\fIcommand\fR]
The
\fB\-s\fR (\fIshell\fR)
option runs the shell specified by the
\fRSHELL\fR
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
\fB\-c\fR
option.
If no command is specified, an interactive shell is executed.
.TP 12n
\fB\-t\fR \fItype\fR
The
\fB\-t\fR (\fItype\fR)
option causes the new (SELinux) security context to have the type
specified by
\fItype\fR.
If no type is specified, the default type is derived from the
specified role.
.TP 12n
\fB\-U\fR \fIuser\fR
The
\fB\-U\fR (\fIother user\fR)
option is used in conjunction with the
\fB\-l\fR
option to specify the user whose privileges should be listed.
The security policy may restrict listing other users' privileges.
The
\fIsudoers\fR
policy only allows root or a user with the
\fRALL\fR
privilege on the current host to use this option.
.TP 12n
\fB\-u\fR \fIuser\fR
The
\fB\-u\fR (\fIuser\fR)
option causes
\fBsudo\fR
to run the specified command as a user other than
\fIroot\fR.
To specify a
\fIuid\fR
instead of a
\fIuser name\fR,
\fI#uid\fR.
When running commands as a
\fIuid\fR,
many shells require that the
`#'
be escaped with a backslash
(`\e').
Security policies may restrict
\fIuid\fRs
to those listed in the password database.
The
\fIsudoers\fR
policy allows
\fIuid\fRs
that are not in the password database as long as the
\fItargetpw\fR
option is not set.
Other security policies may not support this.
.TP 12n
\fB\-V\fR
The
\fB\-V\fR (\fIversion\fR)
option causes
\fBsudo\fR
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
\fB\-V\fR
option will display the arguments passed to configure when
\fBsudo\fR
was built and plugins may display more verbose information such as
default options.
.TP 12n
\fB\-v\fR
When given the
\fB\-v\fR (\fIvalidate\fR)
option,
\fBsudo\fR
will update the user's cached credentials, authenticating the user's
password if necessary.
For the
\fIsudoers\fR
plugin, this extends the
\fBsudo\fR
timeout for another
\fR@timeout@\fR
minutes (or whatever the timeout is set to by the security policy)
but does not run a command.
Not all security policies support cached credentials.
.TP 12n
\fB\--\fR
The
\fB\--\fR
option indicates that
\fBsudo\fR
should stop processing command line arguments.
.PP
Environment variables to be set for the command may also be passed
on the command line in the form of
\fBVAR\fR=\fIvalue\fR,
e.g.\&
\fBLD_LIBRARY_PATH\fR=\fI/usr/local/pkg/lib\fR.
Variables passed on the command line are subject to the same
restrictions as normal environment variables with one important
exception.
If the
\fIsetenv\fR
option is set in
\fIsudoers\fR,
the command to be run has the
\fRSETENV\fR
tag set or the command matched is
\fRALL\fR,
the user may set variables that would otherwise be forbidden.
See
sudoers(@mansectform@)
for more information.
.SH "COMMAND EXECUTION"
When
\fBsudo\fR
executes a command, the security policy specifies the execution
environment for the command.
Typically, 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
\fB\-P\fR
option was specified).
.PP
The following parameters may be specified by security policy:
.TP 4n
\fBo\fR
real and effective user ID
.TP 4n
\fBo\fR
real and effective group ID
.TP 4n
\fBo\fR
supplementary group IDs
.TP 4n
\fBo\fR
the environment list
.TP 4n
\fBo\fR
current working directory
.TP 4n
\fBo\fR
file creation mode mask (umask)
.TP 4n
\fBo\fR
SELinux role and type
.TP 4n
\fBo\fR
Solaris project
.TP 4n
\fBo\fR
Solaris privileges
.TP 4n
\fBo\fR
BSD login class
.TP 4n
\fBo\fR
scheduling priority (aka nice value)
.SS "Process model"
When
\fBsudo\fR
runs a command, it calls
fork(2),
sets up the execution environment as described above, and calls the
execve
system call in the child process.
The main
\fBsudo\fR
process waits until the command has completed, then passes the
command's exit status to the security policy's close function and exits.
If an I/O logging plugin is configured or if the security policy
explicitly requests it, a new  pseudo-terminal
(``pty'')
is created and a second
\fBsudo\fR
process is used to relay job control signals between the user's
existing pty and the new pty the command is being run in.
This extra process makes it possible to, for example, suspend
and resume the command.
Without it, the command would be in what POSIX terms an
``orphaned process group''
and it would not receive any job control signals.
As a special case, if the policy plugin does not define a close
function and no pty is required,
\fBsudo\fR
will execute the command directly instead of calling
fork(2)
first.
.SS "Signal handling"
Because the command is run as a child of the
\fBsudo\fR
process,
\fBsudo\fR
will relay signals it receives to the command.
Unless the command is being run in a new pty, the
\fRSIGHUP\fR,
\fRSIGINT\fR
and
\fRSIGQUIT\fR
signals are not relayed unless they are sent by a user process,
not the kernel.
Otherwise, the command would receive
\fRSIGINT\fR
twice every time the user entered control-C.
Some signals, such as
\fRSIGSTOP\fR
and
\fRSIGKILL\fR,
cannot be caught and thus will not be relayed to the command.
As a general rule,
\fRSIGTSTP\fR
should be used instead of
\fRSIGSTOP\fR
when you wish to suspend a command being run by
\fBsudo\fR.
.PP
As a special case,
\fBsudo\fR
will not relay signals that were sent by the command it is running.
This prevents the command from accidentally killing itself.
On some systems, the
reboot(@mansectsu@)
command sends
\fRSIGTERM\fR
to all non-system processes other than itself before rebooting
the system.
This prevents
\fBsudo\fR
from relaying the
\fRSIGTERM\fR
signal it received back to
reboot(@mansectsu@),
which might then exit before the system was actually rebooted,
leaving it in a half-dead state similar to single user mode.
Note, however, that this check only applies to the command run by
\fBsudo\fR
and not any other processes that the command may create.
As a result, running a script that calls
reboot(@mansectsu@)
or
shutdown(@mansectsu@)
via
\fBsudo\fR
may cause the system to end up in this undefined state unless the
reboot(@mansectsu@)
or
shutdown(@mansectsu@)
are run using the
\fBexec\fR()
family of functions instead of
\fBsystem\fR()
(which interposes a shell between the command and the calling process).
.PP
If no I/O logging plugins are loaded and the policy plugin has not
defined a
\fBclose\fR()
function, set a command timeout or required that the command be
run in a new pty,
\fBsudo\fR
may execute the command directly instead of running it as a child process.
.SS "Plugins"
Plugins are dynamically loaded based on the contents of the
sudo.conf(@mansectform@)
file.
If no
sudo.conf(@mansectform@)
file is present, or it contains no
\fRPlugin\fR
lines,
\fBsudo\fR
will use the traditional
\fIsudoers\fR
security policy and I/O logging.
See the
sudo.conf(@mansectform@)
manual for details of the
\fI@sysconfdir@/sudo.conf\fR
file and the
sudo_plugin(@mansectsu@)
manual for more information about the
\fBsudo\fR
plugin architecture.
.SH "EXIT VALUE"
Upon successful execution of a program, the exit status from
\fIsudo\fR
will simply be the exit status of the program that was executed.
.PP
Otherwise,
\fBsudo\fR
exits with a value of 1 if there is a configuration/permission
problem or if
\fBsudo\fR
cannot execute the given command.
In the latter case the error string is printed to the standard error.
If
\fBsudo\fR
cannot
stat(2)
one or more entries in the user's
\fRPATH\fR,
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
\fRPATH\fR
is on a machine that is currently unreachable.
.SH "SECURITY NOTES"
\fBsudo\fR
tries to be safe when executing external commands.
.PP
To prevent command spoofing,
\fBsudo\fR
checks "." and "" (both denoting current directory) last when
searching for a command in the user's
\fRPATH\fR
(if one or both are in the
\fRPATH\fR).
Note, however, that the actual
\fRPATH\fR
environment variable is
\fInot\fR
modified and is passed unchanged to the program that
\fBsudo\fR
executes.
.PP
Please note that
\fBsudo\fR
will normally only log the command it explicitly runs.
If a user runs a command such as
\fRsudo su\fR
or
\fRsudo sh\fR,
subsequent commands run from that shell are not subject to
\fBsudo\fR'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
\fBsudo\fR
to verify that the command does not inadvertently give the user an
effective root shell.
For more information, please see the
\fIPREVENTING SHELL ESCAPES\fR
section in
sudoers(@mansectform@).
.PP
To prevent the disclosure of potentially sensitive information,
\fBsudo\fR
disables core dumps by default while it is executing (they are
re-enabled for the command that is run).
To aid in debugging
\fBsudo\fR
crashes, you may wish to re-enable core dumps by setting
``disable_coredump''
to false in the
sudo.conf(@mansectform@)
file as follows:
.nf
.sp
.RS 6n
Set disable_coredump false
.RE
.fi
.PP
See the
sudo.conf(@mansectform@)
manual for more information.
.SH "ENVIRONMENT"
\fBsudo\fR
utilizes the following environment variables.
The security policy has control over the actual content of the command's
environment.
.TP 17n
\fREDITOR\fR
Default editor to use in
\fB\-e\fR
(sudoedit) mode if neither
\fRSUDO_EDITOR\fR
nor
\fRVISUAL\fR
is set.
.TP 17n
\fRMAIL\fR
In
\fB\-i\fR
mode or when
\fIenv_reset\fR
is enabled in
\fIsudoers\fR,
set to the mail spool of the target user.
.TP 17n
\fRHOME\fR
Set to the home directory of the target user if
\fB\-i\fR
or
\fB\-H\fR
are specified,
\fIenv_reset\fR
or
\fIalways_set_home\fR
are set in
\fIsudoers\fR,
or when the
\fB\-s\fR
option is specified and
\fIset_home\fR
is set in
\fIsudoers\fR.
.TP 17n
\fRPATH\fR
May be overridden by the security policy.
.TP 17n
\fRSHELL\fR
Used to determine shell to run with
\fB\-s\fR
option.
.TP 17n
\fRSUDO_ASKPASS\fR
Specifies the path to a helper program used to read the password
if no terminal is available or if the
\fB\-A\fR
option is specified.
.TP 17n
\fRSUDO_COMMAND\fR
Set to the command run by sudo.
.TP 17n
\fRSUDO_EDITOR\fR
Default editor to use in
\fB\-e\fR
(sudoedit) mode.
.TP 17n
\fRSUDO_GID\fR
Set to the group ID of the user who invoked sudo.
.TP 17n
\fRSUDO_PROMPT\fR
Used as the default password prompt.
.TP 17n
\fRSUDO_PS1\fR
If set,
\fRPS1\fR
will be set to its value for the program being run.
.TP 17n
\fRSUDO_UID\fR
Set to the user ID of the user who invoked sudo.
.TP 17n
\fRSUDO_USER\fR
Set to the login name of the user who invoked sudo.
.TP 17n
\fRUSER\fR
Set to the target user (root unless the
\fB\-u\fR
option is specified).
.TP 17n
\fRVISUAL\fR
Default editor to use in
\fB\-e\fR
(sudoedit) mode if
\fRSUDO_EDITOR\fR
is not set.
.SH "FILES"
.TP 26n
\fI@sysconfdir@/sudo.conf\fR
\fBsudo\fR
front end configuration
.SH "EXAMPLES"
Note: the following examples assume a properly configured security
policy.
.PP
To get a file listing of an unreadable directory:
.nf
.sp
.RS 6n
$ sudo ls /usr/local/protected
.RE
.fi
.PP
To list the home directory of user yaz on a machine where the file
system holding ~yaz is not exported as root:
.nf
.sp
.RS 6n
$ sudo -u yaz ls ~yaz
.RE
.fi
.PP
To edit the
\fIindex.html\fR
file as user www:
.nf
.sp
.RS 6n
$ sudo -u www vi ~www/htdocs/index.html
.RE
.fi
.PP
To view system logs only accessible to root and users in the adm
group:
.nf
.sp
.RS 6n
$ sudo -g adm view /var/log/syslog
.RE
.fi
.PP
To run an editor as jim with a different primary group:
.nf
.sp
.RS 6n
$ sudo -u jim -g audio vi ~jim/sound.txt
.RE
.fi
.PP
To shut down a machine:
.nf
.sp
.RS 6n
$ sudo shutdown -r +15 "quick reboot"
.RE
.fi
.PP
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
\fRcd\fR
and file redirection work.
.nf
.sp
.RS 6n
$ sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"
.RE
.fi
.SH "SEE ALSO"
su(1),
stat(2),
login_cap(3),
passwd(@mansectform@),
sudo.conf(@mansectform@),
sudoers(@mansectform@),
sudo_plugin(@mansectsu@),
sudoreplay(@mansectsu@),
visudo(@mansectsu@)
.SH "HISTORY"
See the HISTORY file in the
\fBsudo\fR
distribution (http://www.sudo.ws/sudo/history.html) for a brief
history of sudo.
.SH "AUTHORS"
Many people have worked on
\fBsudo\fR
over the years; this version consists of code written primarily by:
.sp
.RS 6n
Todd C. Miller
.RE
.PP
See the CONTRIBUTORS file in the
\fBsudo\fR
distribution (http://www.sudo.ws/sudo/contributors.html) for an
exhaustive list of people who have contributed to
\fBsudo\fR.
.SH "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
\fBsudo\fR.
Also, many programs (such as editors) allow the user to run commands
via shell escapes, thus avoiding
\fBsudo\fR's
checks.
However, on most systems it is possible to prevent shell escapes with the
sudoers(@mansectform@)
plugin's
\fInoexec\fR
functionality.
.PP
It is not meaningful to run the
\fRcd\fR
command directly via sudo, e.g.,
.nf
.sp
.RS 6n
$ sudo cd /usr/local/protected
.RE
.fi
.PP
since when the command exits the parent process (your shell) will
still be the same.
Please see the
\fIEXAMPLES\fR
section for more information.
.PP
Running shell scripts via
\fBsudo\fR
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).
.SH "BUGS"
If you feel you have found a bug in
\fBsudo\fR,
please submit a bug report at http://www.sudo.ws/sudo/bugs/
.SH "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.
.SH "DISCLAIMER"
\fBsudo\fR
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
\fBsudo\fR
or http://www.sudo.ws/sudo/license.html for complete details.