Document the EXTLINUX ADV commands.

diff --git a/extlinux.doc b/extlinux.doc
index 78f0910..2508fa1 100644 (file)
--- a/extlinux.doc
+++ b/extlinux.doc
@@ -6,7 +6,7 @@ It works the same way as SYSLINUX, with a few slight modifications.
 1. The installer is run on a *mounted* filesystem.  Run the extlinux
    installer on the directory in which you want extlinux installed:
 
-       extlinux -i /boot
+       extlinux --install /boot
 
    Specify --install (-i) to install for the first time, or
    --update (-U) to upgrade a previous installation.
@@ -15,9 +15,10 @@ It works the same way as SYSLINUX, with a few slight modifications.
    If /boot is a filesystem, you can do:
 
        mkdir -p /boot/extlinux
-       extlinux -i /boot/extlinux
+       extlinux --install /boot/extlinux
 
    ... to create a subdirectory and install extlinux in it.
+   /boot/extlinux is the recommended location for extlinux.
 
 
 2. The configuration file is called "extlinux.conf", and is expected
@@ -42,6 +43,39 @@ It works the same way as SYSLINUX, with a few slight modifications.
    possible.
 
 
+5. EXTLINUX now has "boot-once" support.  The boot-once information is
+   stored in an on-disk datastructure, part of extlinux.sys, called
+   the "Auxillary Data Vector".  The Auxilliary Data Vector is also
+   available to COMBOOT/COM32 modules that want to store small amounts
+   of information.
+
+   To set the boot-once information, do:
+
+       extlinux --once 'command' /boot/extlinux
+
+   where 'command' is any command you could enter at the SYSLINUX
+   command line.  It will be executed on the next boot and then
+   erased.
+
+   To clear the boot-once information, do:
+
+       extlinux --clear-once /boot/extlinux
+
+   If EXTLINUX is used on a RAID-1, this is recommended, since under
+   certain circumstances a RAID-1 rebuild can "resurrect" the
+   boot-once information otherwise.
+
+   To clear the entire Auxillary Data Vector, do:
+
+       extlinux --reset-adv /boot/extlinux
+
+   This will erase all data stored in the ADV, including boot-once.
+
+   The --once, --clear-once, and --reset-adv commands can be combined
+   with --install or --update, if desired.  The ADV is preserved
+   across updates, unless --reset-adv is specified.
+   
+
 Note that EXTLINUX installs in the filesystem partition like a
 well-behaved bootloader :)  Thus, it needs a master boot record in the
 partition table; the mbr.bin shipped with SYSLINUX should work well.