+This option is useful in conjunction with the \fI-v\fP flag to
+determine what the
+.I mount
+command is trying to do.
+.PP
+The optional argument \fI-t\fP can be used
+to indicate the file system type.
+The type \fBufs\fP is the default.
+If the type is not one of the internally known types,
+mount will attempt to execute a program in
+.B /sbin/mount_XXX
+where \fBXXX\fP is replaced by the type name.
+The standard mount options (see below) are parsed and
+passed to external program via the \fI-F\fP option
+as a decimal number.
+Any additional options specific to the program can
+be passed as a comma separated list;
+these options are distinguished by starting with a \fI-\fP (dash).
+Those options that take a value are specified
+using the syntax -option=value.
+For example, the mount command:
+.br
+ mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp
+.br
+causes mount to attempt to execute:
+.br
+ /sbin/mount_mfs -F 8 -N -s 4000 /dev/dk0b /tmp
+.PP
+Options are specified by a \fI-o\fP argument
+followed by a comma separated string of options.
+The following options apply to any file system that is being mounted:
+.IP "noexec" 12
+Do not allow execution of any binaries on the mounted file system.
+This options is useful for a server that has file systems containing
+binaries for architectures other than its own.
+.IP "nosuid" 12
+Do not allow set-user-identifier or set-group-identifier bits to take effect.
+.IP "nodev" 12
+Do not interpret character or block special devices on the file system.
+This options is useful for a server that has file systems containing
+special devices for architectures other than its own.
+.IP "synchronous" 12
+All I/O to the file system should be done synchronously.
+.PP
+The \fI-u\fP flag indicates that the status of an already mounted file
+system should be changed.
+Any of the options above may be changed;
+also a file system can be changed from read-only to read-write.
+The set of options is determined by first extracting the options
+for the file system from the \fIfstab\fP table,
+then applying any options specified by the \fI-o\fP argument,
+and finally applying the \fI-r\fP or \fI-w\fP option.