Update README file

tools/README.txt

@@ -21,7 +21,7 @@ astyle.sh
 Config.mk
 ---------
 
-  This file contains common definitions used by many configureation files.
+  This file contains common definitions used by many configuration files.
   This file (along with <nuttx>/.config) must be included at the top of
   each configuration-specific Make.defs file like:
 
@@ -48,7 +48,7 @@ configure.c, cfgparser.c, and cfgparser.h
 
   configure.bat is a small Windows batch file that can be used as a replacement
   for configure.sh in a Windows native environment.  configure.bat is actually
-  just a thin layer that execuates configure.exe if it is available. If
+  just a thin layer that executes configure.exe if it is available. If
   configure.exe is not available, then configure.bat will attempt to build it
   first.
 
@@ -94,7 +94,7 @@ kconfig2html.c
   This is a C file that can be used build a utility for converting the
   NuttX configuration in the Kconfig files to an HTML document.  This
   auto-generated documentation will, eventually, replace the manually
-  updated configuratin documentation that is fallling woefully behind.
+  updated configuration documentation that is fallling woefully behind.
 
   $ tools/kconfig2html.exe -h
   USAGE: tools/kconfig2html [-d] [-a <apps directory>] {-o <out file>] [<Kconfig root>]
@@ -114,7 +114,7 @@ mkconfigvars.sh
 ---------------
 
   The HTML documentation expects to have a copy of the auto-generated
-  configuration variabled documentation Documentation/NuttXConfigVariables.html.
+  configuration variable documentation Documentation/NuttXConfigVariables.html.
   The script mkconfigvars.sh is a simple script that can be used to
   re-generated that file as needed.
 
@@ -234,7 +234,7 @@ bdf-convert.c
     1. Locate a font in BDF format,
     2. Use the bdf-converter program to convert the BDF font to the NuttX
        font format.  This will result in a C header file containing
-       defintions.  That header file should be installed at, for example,
+       definitions.  That header file should be installed at, for example,
        graphics/nxfonts/nxfonts_myfont.h.
 
   Create a new NuttX configuration variable.  For example, suppose
@@ -274,7 +274,7 @@ bdf-convert.c
 
   New Add the font to the NX build system.  There are several files that
   you have to modify to to this.  Look how the build system uses the
-  font CONFIG_NXFONT_SANS23X27 for examaples:
+  font CONFIG_NXFONT_SANS23X27 for examples:
 
     5. nuttx/graphics/Makefile.  This file needs logic to auto-generate
        a C source file from the header file that you generated with the
@@ -305,7 +305,7 @@ bdf-convert.c
        in step 5 that will actually generate the font C file.  So, given
        your NXFONTS_FONTID=2, it needs to determine a prefix to use for
        auto-generated variable and function names and (again) the name of
-       the autogenerated file to create (this must be the same name that
+       the auto-generated file to create (this must be the same name that
        was used in nuttx/graphics/nxfonts/Make.defs):
 
        ifeq ($(NXFONTS_FONTID),1)
@@ -399,7 +399,7 @@ mknulldeps.sh
   NOTE:  The mk*deps.* files are undergoing change.  mkdeps.sh is a bash
   script that produces dependencies well for POSIX style hosts (e..g.,
   Linux and Cygwin).  It does not work well for mixed environments with
-  a Windows toolchain running in a POSIX style environemnt (hence, the
+  a Windows toolchain running in a POSIX style environment (hence, the
   mknulldeps.sh script).  And, of course, cannot be used in a Windows
   nativ environment.
 
@@ -536,6 +536,38 @@ indent.sh
 
   See astyle.sh above.  I suspect that it will do a better job.
 
+refresh.sh
+----------
+
+  This is a bash script that automatics refreshing of board default
+  configuration (defconfig) files.  It does not do anything special
+  thet you cannot do manually, but is useful for me when I have to
+  update dozens of confuration files.
+
+  Configuration files have to be updated because over time, the
+  configuration settings change:  New configurations are added and
+  new dependencies are added.  So an old configuration file may
+  not be usable anymore until it is refreshed.
+
+  The steps to refresh the file are:
+
+  1. Make tools/cmpconfig if it is not already built.
+  2. Copy the the defconfig file to the top-level NuttX
+     directory as .config (being careful to save any previous
+     .config file that you might want to keep!).
+  3. Execute 'make oldconfig' to update the configuration.
+     'make oldconfig' will prompt you for each change in the
+     configuration that requires that you make some decision.
+  4. Then it runs tools/cmpconfig to show the real differences
+     between the configuration files.  Configuration files are
+     complex and things can move around so a simple 'diff' between
+     two configuration files is often not useful.  But tools/cmpconfig
+     will show only the meaningful differences between the two
+     configuration files.
+  5. Finally, the refreshed defconfig file is copied back in
+     place where it can be committed with the next set of
+     difference (unless you add --dry-run) to the command line.
+`
 zipme.sh
 --------