+.SS "Including other files from within sudoers"
+.IX Subsection "Including other files from within sudoers"
+It is possible to include other \fIsudoers\fR files from within the
+\&\fIsudoers\fR file currently being parsed using the \f(CW\*(C`#include\*(C'\fR and
+\&\f(CW\*(C`#includedir\*(C'\fR directives.
+.PP
+This can be used, for example, to keep a site-wide \fIsudoers\fR file
+in addition to a local, per-machine file. For the sake of this
+example the site-wide \fIsudoers\fR will be \fI/etc/sudoers\fR and the
+per-machine one will be \fI/etc/sudoers.local\fR. To include
+\&\fI/etc/sudoers.local\fR from within \fI/etc/sudoers\fR we would use the
+following line in \fI/etc/sudoers\fR:
+.Sp
+.RS 4
+\&\f(CW\*(C`#include /etc/sudoers.local\*(C'\fR
+.RE
+.PP
+When \fBsudo\fR reaches this line it will suspend processing of the
+current file (\fI/etc/sudoers\fR) and switch to \fI/etc/sudoers.local\fR.
+Upon reaching the end of \fI/etc/sudoers.local\fR, the rest of
+\&\fI/etc/sudoers\fR will be processed. Files that are included may
+themselves include other files. A hard limit of 128 nested include
+files is enforced to prevent include file loops.
+.PP
+The file name may include the \f(CW%h\fR escape, signifying the short form
+of the host name. I.e., if the machine's host name is \*(L"xerxes\*(R", then
+.PP
+\&\f(CW\*(C`#include /etc/sudoers.%h\*(C'\fR
+.PP
+will cause \fBsudo\fR to include the file \fI/etc/sudoers.xerxes\fR.
+.PP
+The \f(CW\*(C`#includedir\*(C'\fR directive can be used to create a \fIsudo.d\fR
+directory that the system package manager can drop \fIsudoers\fR rules
+into as part of package installation. For example, given:
+.PP
+\&\f(CW\*(C`#includedir /etc/sudoers.d\*(C'\fR
+.PP
+\&\fBsudo\fR will read each file in \fI/etc/sudoers.d\fR, skipping file
+names that end in \f(CW\*(C`~\*(C'\fR or contain a \f(CW\*(C`.\*(C'\fR character to avoid causing
+problems with package manager or editor temporary/backup files.
+Files are parsed in sorted lexical order. That is,
+\&\fI/etc/sudoers.d/01_first\fR will be parsed before
+\&\fI/etc/sudoers.d/10_second\fR. Be aware that because the sorting is
+lexical, not numeric, \fI/etc/sudoers.d/1_whoops\fR would be loaded
+\&\fBafter\fR \fI/etc/sudoers.d/10_second\fR. Using a consistent number
+of leading zeroes in the file names can be used to avoid such
+problems.
+.PP
+Note that unlike files included via \f(CW\*(C`#include\*(C'\fR, \fBvisudo\fR will not
+edit the files in a \f(CW\*(C`#includedir\*(C'\fR directory unless one of them
+contains a syntax error. It is still possible to run \fBvisudo\fR
+with the \f(CW\*(C`\-f\*(C'\fR flag to edit the files directly.
+.SS "Other special characters and reserved words"