I have a requirement to convert .KML file to GeoJSON or JSON. Can you please recommend open source command line tools on GNU/Linux(2.6.32-358.14.1.el6.x86_64)? I have installed gdal, I am getting below error.

ogr2ogr -f "GeoJSON" geojson.json Areas.kml

Unable to open datasource `Areas.kml' with the following drivers. -> ESRI Shapefile -> MapInfo File -> UK .NTF -> SDTS -> TIGER -> S57 -> DGN -> VRT -> REC -> Memory -> BNA -> CSV -> GML -> GPX -> KML -> GeoJSON -> GMT -> AVCBin