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3.28 History Attribute

Availability: All operators
Short options: ‘-h
Long options: ‘--hst’, ‘--history
All operators automatically append a history global attribute to any file they create or modify. The history attribute consists of a timestamp and the full string of the invocation command to the operator, e.g., ‘Mon May 26 20:10:24 1997: ncks in.nc foo.nc’. The full contents of an existing history attribute are copied from the first input-file to the output-file. The timestamps appear in reverse chronological order, with the most recent timestamp appearing first in the history attribute. Since NCO and many other netCDF operators adhere to the history convention, the entire data processing path of a given netCDF file may often be deduced from examination of its history attribute. As of May, 2002, NCO is case-insensitive to the spelling of the history attribute name. Thus attributes named History or HISTORY (which are non-standard and not recommended) will be treated as valid history attributes. When more than one global attribute fits the case-insensitive search for "history", the first one found will be used. history attribute To avoid information overkill, all operators have an optional switch (‘-h’, ‘--hst’, or ‘--history’) to override automatically appending the history attribute (see ncatted netCDF Attribute Editor). Note that the ‘-h’ switch also turns off writing the nco_input_file_list attribute for multi-file operators (see File List Attributes).