NAME

       ncoffsets - print the starting/ending file offsets for netCDF variables

SYNOPSIS

       ncoffsets [-h] | [-x] | [-sgr] [-v var1[,...]]  file

DESCRIPTION

       ncoffsets prints the file offsets information of variables defined in a given netCDF file.
       The ending offsets reported is an exclusive offset, i.e.  1 byte more than the  last  byte
       occupied  by  the  variable.  In  other  words,  the  ending offset is equal to the sum of
       starting offset and the variable size.  For record variables, only the  offsets  of  first
       record are printed. Add option -r to print the offsets of all records.

       If no argument is given, command usage information is printed.

OPTIONS

       -v var1[,...]
              The  output  will  include  data  values  for  the specified variables. One or more
              variables must be specified by name in  the  comma-delimited  list  following  this
              option.   The  list  must be a single argument to the command, hence cannot contain
              blanks or other white space characters.  The named variables must be  valid  netCDF
              variables  in  the input file.  The default, without this option is to include data
              values for all variables in the output.

       -s     Print the variable size in bytes. For record variables, only the size of one record
              is printed.

       -g     Print  the gap in bytes from the previous variable. For the first defined variable,
              print the gap from the end of file header. For record variables, there  is  no  gap
              between records.

       -r     Output  the  offset  information  for all records of the selected record variables.
              Without this option, only the offsets of first record are printed.

       -x     Check all fixed-size variable for file space gaps in between  any  two  immediately
              adjacent  variables.  It prints "1" on stdout if gaps are found, "0" for otherwise.
              This option disables all other options.

       -h     Print the available command-line options

EXAMPLES

       Print the file offset information for all variables in a netCDF file.

       % ncoffsets -sg testfile.nc
       netcdf testfile.nc {
       //file format: CDF-1

       file header:
            size   = 340 bytes
            extent = 340 bytes

       dimensions:
            x = 100
            y = 100
            z = 100
            time = UNLIMITED // (100 currently)

       fixed-size variables:
            double square(x, y):
                   start file offset =         340
                   end   file offset =       80340
                   size in bytes     =       80000
                   gap from prev var =           0
            double cube(x, y, z):
                   start file offset =       80340
                   end   file offset =     8080340
                   size in bytes     =     8000000
                   gap from prev var =           0

       record variables:
            double time(time):
                   start file offset =     8080340    (record 0)
                   end   file offset =     8081140    (record 0)
                   size in bytes     =           8    (of one record)
                   gap from prev var =           0
            double xytime(time, x, y):
                   start file offset =     8080348    (record 0)
                   end   file offset =    16080348    (record 0)
                   size in bytes     =       80000    (of one record)
                   gap from prev var =           0
       }

       Check if there are gaps in between two adjacent fixed-size variables.

       % ncoffsets -x testfile.nc
       0

SEE ALSO

       pnetcdf(3)

DATE

       February 21, 2022