/*!  \page grib_index_build grib_index_build
\section DESCRIPTION 
 Build an index file for a set of input grib files.

\section USAGE 
 grib_index_build 
 [options] grib_file grib_file ... 

\section OPTIONS 
-f  \n Force. Force the execution not to fail on error.
 \n \n -o output_index_file \n 
		Output is written to output_index_file.
		If an output index file is required and -o is not used, the output index is written to gribidx
 \n \n -k key1,key2,... \n 
		Specify a list of keys to index on. By default the input files are indexed on the MARS keys.
		For each key a string (key:s) or a double (key:d) or an integer (key:i)
		type can be requested.
 \n \n -V  \n Version.
 \n \n -T T | B | M | A \n Message type. T->GTS, B->BUFR, M->METAR (Experimental),A->Any (Experimental).
			The input file is interpreted according to the message type.
 \n \n -M  \n Multi-field support off. Turn off support for multiple fields in single grib message.
 \n \n -N  \n Do not compress index.
		By default the index is compressed to remove keys with only one value.
 \n \n 
\section grib_index_build_examples grib_index_build examples
-# By default grib_index_build will index on the MARS keys. \n
\verbatim 
> grib_index_build ../data/reduced*.grib1 ../data/regular*.grib1 ../data/reduced*.grib2
\endverbatim\n 
-# To specify a custom list of keys to index on, use the -k option.\n 
\verbatim 
> grib_index_build -k paramId,dataDate ../data/reduced*.grib1 ../data/regular*.grib1 ../data/reduced*.grib2
\endverbatim\n 
*/