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+# GRUB EDITOR
+
+Libreboot ROM images now support fluid _grub.cfg_ and _grubtest.cfg_
+configuration editing with the grubeditor.sh script! Instead of manually running
+cbfstool to manipulate these configuration files, this script will handle the
+work for you so you can focus on actually modifying your GRUB configuration
+files to your setup's needs.
+
+At the time of this writing, grubeditor.sh supports extracting and editing
+either the grub.cfg or grubtest.cfg file in any cbfstool-compatible Libreboot
+ROM image that contains these files, even ones that have been previously
+modified. It can also swap these configuration files in an existing ROM image,
+handy if you have a working grubtest.cfg and want to make it the default or if
+you broke the main grub.cfg and know that your grubtest.cfg still works. Lastly,
+it can also run diff on these two configuration files to show you how they
+differ.
+
+## Requirements
+
+grubeditor.sh requires an x86, x86\_64, or armv7l environment, since these are
+the environments for which cbfstools binaries are provided. Additionally,
+grubeditor.sh needs a Bash environment with extended getopt functionality that
+can run the **diff** command and write to /tmp. Lastly, the script expects to
+live in the top directory of the Libreboot utilities package so it can properly
+call cbfstool.
+
+Chances are that you already meet these requirements if you are on a Linux
+environment of the listed architectures and downloaded the Libreboot utilities
+package from an official source. If not, it shouldn't be too hard to use a
+Linux LiveCD of your choice which provides these essentials.
+
+Optionally, you should make sure your EDITOR variable is set. Otherwise,
+grubeditor.sh will default to using vi, which may not exist on your system. You
+can override this default or the contents of your EDITOR variable using the
+**-e** or **--editor** command.
+
+## Usage help
+
+grubeditor.sh takes a number of options, the only one which is required being a
+valid Libreboot ROM image that uses the GRUB2 payload and contains both
+_grub.cfg_ and _grubtest.cfg_ files. Additional options should come _before_ the
+ROM image file on the command line.
+
+grubeditor.sh supports combining several short options with a single hyphen
+like **-ris**, but you can also list them separately like **-r -i -s**. Long
+options must always be written as standalone arguments.
+
+You can use the **-h** or **--help** option to view a brief summary of the
+options available. Consider this guide a more extensive version of this screen.
+
+Lastly, you can check which version of grubeditor.sh you are using with the
+**-v** or **--version** option.
+
+## Editing configuration files
+
+Invoked without any arguments except for the ROM image, grubeditor.sh will
+attempt to extract the _grubtest.cfg_ file from the provided ROM image and
+launch it in your editor of choice. If you make changes to the file,
+grubeditor.sh will incorporate your changes into a new ROM image with the same
+name in the same directory, except that the new ROM file will end with
+".modified". You can then flash this ROM image to your platform's BIOS chip.
+
+If you would prefer to edit the actual _grub.cfg_ configuration file, use the
+**-r** or the **--realcfg** option. Everything else will work the same except
+that your editor will open the _grub.cfg_ instead. 
+
+If you would prefer to overwrite your existing ROM image instead of creating a
+new one ending in ".modified" use the **-i** or **--inplace** option.
+Naturally, you can combine this option with the **-r/--realcfg** option
+described above.
+
+## Swapping grub.cfg and grubtest.cfg
+
+grubeditor.sh supports swapping the _grub.cfg_ and _grubtest.cfg_ configuration
+files with the **-s** or **--swap** option. This will create a new ROM image
+alongside the existing ROM image ending with ".modified" which has these files
+swapped. Naturally, you can request this operation overwrite the existing file
+instead using the **-i/--inplace** option.
+
+Note that the script will automatically modify the "Load test configuration
+(grubtest.cfg)" menu entry in both configuration files during this operation.
+If this was not done, these entries would end up being self-referential after
+the rename, breaking their intended functionality of changing between the
+configuration files.
+
+For best results, please do not modify this section without studying the source
+code of _grubeditor.sh_ and making sure your edits do not impact the script's
+ability to perform this modification
+
+## Swapping grub.cfg and grubtest.cfg
+
+grubeditor.sh supports comparing _grub.cfg_ and _grubtest.cfg_ files for
+differences with the **-d** or **--diffcfg** option. This uses the diff command
+by default, but if you want to use another program (e.g. vimdiff), you can
+specify it with the **-D** or **--differ** option. Note that this mode is only
+intended to show differences in the files and does not support updating the
+configs themselves, so any changes you make in an interactive differ will be
+ignored.
+
+## Extracting a configuration file
+
+You can simply extract a configuration file using the **-x** or **--extract**
+option. This option is responsive to the **-r/--realcfg** option for choosing
+between grubtest.cfg and grub.cfg.
+
+## Pending development
+
+TODO:
+-   allow injecting configuration files to complement the extractor.
+-   detect potentially devastating corner cases, however rare they may actually be
+-   i can't specify a quoted command line with arguments to -e or -D, why?
+-   support editing both config files if using an interactive differ
+-   work with other types of files besides the grub configuration files.
+
+## Conclusion
+
+I hope that grubeditor.sh will significantly ease modifying your configuration
+files in your Libreboot ROM files.
+
+Should you find any bugs or want any feature requests, please don't hesitate to
+email me or bug me on IRC.