The netCDF Operators (NCO) comprise a dozen standalone, command-line programs that take netCDF files as input, then operate (e.g., derive new data, average, print, hyperslab, manipulate metadata) and output the results to screen or files in text, binary, or netCDF formats. NCO aids manipulation and analysis of gridded scientific data. The shell-command style of NCO allows users to manipulate and analyze files interactively, or with simple scripts that avoid some overhead (and power) of higher level programming environments. The NCO User's Guide illustrates their use with examples of climate data analysis: ncap2 (netCDF Arithmetic Processor); ncatted netCDF ATTribute EDitor; ncbo netCDF Binary Operator (includes ncadd, ncsubtract, ncmultiply, ncdivide); ncea netCDF Ensemble Averager; ncecat;netCDF Ensemble conCATenator; ncflint netCDF FiLe INTerpolator: ncks netCDF Kitchen Sink; ncpdq netCDF Permute Dimensions Quickly, Pack Data Quietly; ncra netCDF Record Averager; ncrcat; netCDF Record conCATenator; ncrename netCDF RENAMEer; ncwa netCDF Weighted Averager.|
Note that the “averagers” (ncea and ncra) are misnamed because they perform many non-linear operations as well, e.g., total, minimum, maximum, RMS. Moreover, ncap2 implements a powerful domain language which handles arbitrarily complex operations. The operators are as general as netCDF itself: there are no restrictions on the contents of the netCDF file(s) used as input. NCO's internal routines are completely dynamic and impose no limit on the number or sizes of dimensions, variables, and files.
NCO is designed to be used both interactively and with large batch jobs. The default operator behavior is often sufficient for everyday needs, and there are numerous command line (i.e., run-time) options, for special cases. NCO works well and is used on most modern operating systems.