ncdump

ncdump is a command-line utility in the NetCDF software suite that prints a human-readable representation of the contents of a NetCDF file. It outputs information in CDL (the NetCDF Description Language), describing the file’s dimensions, variables, data types, and global and variable attributes. The produced CDL can be fed to the ncgen tool to recreate a NetCDF file, making ncdump useful for data exchange, debugging, and archival.

The typical default behavior is to display both the header (structure) and the data values of variables. Users can direct the output to standard output or redirect it to a file, for example by running ncdump file.nc > file.cdl. Common options include -h to print only the header, -v var1,var2 to dump only specified variables, and -d dim,start,count to dump data along a given dimension. Additional options exist to tailor the dump, but exact syntax is documented in the tool’s help or man page.

ncdump supports NetCDF formats, including the classic and NetCDF-4/HDF5 varieties. It is widely available as part of the NetCDF distribution maintained by Unidata and is compatible with common NetCDF workflows across platforms. While highly useful for inspecting and sharing metadata and data, ncdump can produce very large textual outputs for big datasets, so users may apply selective dumping or limit data ranges when dealing with large files.

See also: ncgen, NetCDF, NetCDF libraries.