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ncrename [-a old_name,new_name] [-a ...] [-D dbg] [-d old_name,new_name] [-d ...] [-h] [--hdr_pad nbr] [-l path] [-O] [-o output-file] [-p path] [-R] [-r] [-v old_name,new_name] [-v ...] input-file [[output-file]]
DESCRIPTION
ncrename renames dimensions, variables, and attributes in a netCDF file. Each object that has a name in the list of old names is renamed using the corresponding name in the list of new names. All the new names must be unique. Every old name must exist in the input file, unless the old name is preceded by the period (or “dot”) character ‘.’. The validity of old_name is not checked prior to the renaming. Thus, if old_name is specified without the the ‘.’ prefix and is not present in input-file, ncrename will abort. The new_name should never be prefixed by a ‘.’ (or else the period will be included as part of the new name). The OPTIONS and EXAMPLES show how to select specific variables whose attributes are to be renamed.
ncrename is the exception to the normal rules that the user will
be interactively prompted before an existing file is changed, and that a
temporary copy of an output file is constructed during the operation.
If only input-file is specified, then ncrename will change
the names of the input-file in place without prompting and without
creating a temporary copy of input-file
.
This is because the renaming operation is considered reversible if the
user makes a mistake.
The new_name can easily be changed back to old_name by using
ncrename one more time.
Note that renaming a dimension to the name of a dependent variable can be used to invert the relationship between an independent coordinate variable and a dependent variable. In this case, the named dependent variable must be one-dimensional and should have no missing values. Such a variable will become a coordinate variable.
According to the netCDF User's Guide, renaming properties in netCDF files does not incur the penalty of recopying the entire file when the new_name is shorter than the old_name.
OPTIONS
Rename the variable p
to pressure
and t
to
temperature
in netCDF in.nc.
In this case p
must exist in the input file (or
ncrename will abort), but the presence of t
is optional:
ncrename -v p,pressure -v .t,temperature in.nc
Rename the attribute long_name
to largo_nombre
in the
variable u
, and no other variables in netCDF in.nc.
ncrename -a u:long_name,largo_nombre in.nc
ncrename does not automatically attach dimensions to variables of the same name. If you want to rename a coordinate variable so that it remains a coordinate variable, you must separately rename both the dimension and the variable:
ncrename -d lon,longitude -v lon,longitude in.nc
Create netCDF out.nc identical to in.nc except the
attribute _FillValue
is changed to missing_value
,
the attribute units
is changed to CGS_units
(but only in
those variables which possess it), the attribute hieght
is
changed to height
in the variable tpt
, and in the
variable prs_sfc
, if it exists.
ncrename -a _FillValue,missing_value -a .units,CGS_units \ -a tpt@hieght,height -a prs_sfc@.hieght,height in.nc out.nc
The presence and absence of the ‘.’ and ‘@’ features
cause this command to execute successfully only if a number of
conditions are met.
All variables must have a _FillValue
attribute and
_FillValue
must also be a global attribute.
The units
attribute, on the other hand, will be renamed to
CGS_units
wherever it is found but need not be present in
the file at all (either as a global or a variable attribute).
The variable tpt
must contain the hieght
attribute.
The variable prs_sfc
need not exist, and need not contain the
hieght
attribute.