code: function getCmd(program, opt) {
              var cmd,
                  expr;
  
              if(program==='ogr2ogr') {
  
                  if(opt==='where') {
                      expr = [
                          '-where ',
                          "\"", specs.key, " IN ",
                          "('", specs.val, "')\" ",
                          '-clipsrc ',
                          specs.bounds.join(' ')
                      ].join('');
                  }
                  else if(opt==='clipsrc') {
                      expr = [
                          '-clipsrc ',
                          specs.bounds.join(' ')
                      ].join('');
                  }
                  else  expr = '';
  
                  cmd = [
                      "ogr2ogr -f GeoJSON",
                      expr,
                      common.geojsonDir + common.tn(r, s.name, v.name, 'geo.json'),
                      common.wgetDir + common.srcPrefix + common.bn(r, v.src, 'shp')
                  ].join(' ');
  
              }
              else if(program==='mapshaper') {
                  cmd = [
                      mapshaper,
                      common.wgetDir + common.srcPrefix + common.bn(r, v.src, 'shp'),
                      "encoding=utf8",
                      "-clip",
                      common.wgetDir + common.tn(r, s.name, specs.src, 'shp'),
                      "-filter remove-empty",
                      "-o",
                      common.geojsonDir + common.tn(r, s.name, v.name, 'geo.json')
                 ].join(' ');
              }
  
              return cmd;
          }
docs: use ogr2ogr for clip around bound use mapshaper for clip around shapefile polygons