+
+
+@item -d,--define-default=@var{var}=@var{val}
+This sets the internal program option @var{var} to the Scheme value
+@var{val}. If @var{val} is not supplied, then @var{#t} is used. To
+switch off an option, @code{no-} may be prefixed to @var{var}, e.g.
+
+@cindex point and click, command line
+
+@example
+-dno-point-and-click
+@end example
+
+@noindent
+is the same as
+@example
+-dpoint-and-click='#f'
+@end example
+
+Here are a few interesting options.
+
+@table @samp
+@item help
+Running @code{lilypond -dhelp} will print all of the @code{-d} options
+available.
+
+@item paper-size
+This option sets the default paper-size,
+@example
+-dpaper-size=\"letter\"
+@end example
+
+@noindent
+Note that the string must be enclosed in escaped quotes ( @code{\"} ).
+
+
+@item safe
+Do not trust the @code{.ly} input.
+
+When LilyPond formatting is available through a web server, either the
+@code{--safe} or the @code{--jail} option @b{MUST} be passed. The
+@code{--safe} option will prevent inline Scheme code from wreaking
+havoc, for example
+
+@quotation
+@verbatim
+#(system "rm -rf /")
+{
+ c4^#(ly:export (ly:gulp-file "/etc/passwd"))
+}
+@end verbatim
+@end quotation
+
+The @code{-dsafe} option works by evaluating in-line Scheme
+expressions in a special safe module. This safe module is derived from
+GUILE @file{safe-r5rs} module, but adds a number of functions of the
+LilyPond API. These functions are listed in @file{scm/@/safe@/-lily@/.scm}.
+
+In addition, safe mode disallows @code{\include} directives and
+disables the use of backslashes in @TeX{} strings.
+
+In safe mode, it is not possible to import LilyPond variables
+into Scheme.
+
+safe does @emph{not} detect resource overuse. It is still possible to
+make the program hang indefinitely, for example by feeding cyclic data
+structures into the backend. Therefore, if using LilyPond on a
+publicly accessible webserver, the process should be limited in both
+CPU and memory usage.
+
+The safe mode will prevent many useful LilyPond snippets from being
+compiled. The @code{--jail} is a more secure alternative, but
+requires more work to set up.
+
+@item backend