Provided by: nco_4.7.9-1_amd64 bug

NAME

       ncatted - netCDF Attribute Editor

SYNTAX

       ncatted  [-a  att_dsc] [-a ...] [--bfr sz_byt][-D dbg_lvl] [--glb att_name= att_val]] [-h]
       [--hdr_pad sz_byt] [-l path] [-O] [-p  path]  [-R]  [-r]  [--ram_all]  [-t]  input-file  [
       output-file]

DESCRIPTION

       ncatted  edits  attributes  in  a netCDF file.  If you are editing attributes then you are
       spending too much time in the world of metadata, and ncatted was written to get  you  back
       out  as  quickly  and painlessly as possible.  ncatted can append, create, delete, modify,
       and overwrite attributes (all explained below).  Furthermore, ncatted allows each  editing
       operation to be applied to every variable in a file, thus saving you time when you want to
       change attribute conventions throughout a file.  ncatted interprets  character  attributes
       as strings.

       Because  repeated  use of ncatted can considerably increase the size of the history global
       attribute, the -h switch is provided to override automatically appending  the  command  to
       the history global attribute in the output-file.

       When ncatted is used to change the _FillValue attribute, it changes the associated missing
       data self-consistently.  If the internal floating point representation of a missing value,
       e.g.,  1.0e36,  differs  between two machines then netCDF files produced on those machines
       will have incompatible missing values.  This allows ncatted to change the  missing  values
       in  files  from  different  machines  to  a  single  value  so  that the files may then be
       concatenated together, e.g., by ncrcat, without losing any information.

       The key to mastering ncatted is understanding the meaning of the structure describing  the
       attribute  modification,  att_dsc.  Each att_dsc contains five elements, which makes using
       ncatted somewhat complicated, but powerful.  The att_dsc argument structure contains  five
       arguments in the following order:

       att_dsc = att_nm, var_nm, mode, att_type, att_val

       att_nm Attribute name.  Example: units

       var_nm Variable name.  Example: pressure

       mode   Edit  mode  abbreviation.   Example:  a.   See  below for complete listing of valid
              values of mode.

       att_type
              Attribute type abbreviation. Example: c.  See below for complete listing  of  valid
              values of att_type.

       att_val
              Attribute  value.  Example:  pascal.   There should be no empty space between these
              five consecutive arguments.  The description of these arguments  follows  in  their
              order of appearance.

       The  value  of att_nm is the name of the attribute you want to edit.  This meaning of this
       should be clear to all users of the ncatted operator.

       The value of var_nm is the name of the variable containing the  attribute  (named  att_nm)
       that  you  want to edit.  There are two very important and useful exceptions to this rule.
       The value of var_nm can also be used to direct ncatted to edit global  attributes,  or  to
       repeat  the  editing operation for every variable in a file.  A value of var_nm of global”
       indicates that att_nm refers to a global attribute, rather than  a  particular  variable's
       attribute.   This is the method ncatted supports for editing global attributes.  If var_nm
       is left blank, on the other hand, then ncatted attempts to perform the  editing  operation
       on  every  variable  in  the  file.  This option may be convenient to use if you decide to
       change the conventions you use for describing the data.

       The value of mode is a single character abbreviation ( a, c, d, m, or o) standing for  one
       of five editing modes:

       a      Append.   Append value att_val to current var_nm attribute att_nm value att_val, if
              any.  If var_nm does not have  an  attribute  att_nm,  it  is  created  with  value
              att_val.

       c      Create.   Create  variable  var_nm attribute att_nm with att_val if att_nm does not
              yet exist.  If var_nm already has an attribute att_nm, there is no effect.

       d      Delete.  Delete current var_nm attribute  att_nm.   If  var_nm  does  not  have  an
              attribute  att_nm,  there is no effect.  When Delete mode is selected, the att_type
              and att_val arguments are superfluous and may be left blank.

       m      Modify.  Change value of current var_nm attribute  att_nm  to  value  att_val.   If
              var_nm does not have an attribute att_nm, there is no effect.

       n      Nappend.  Append value att_val to current var_nm attribute att_nm value att_val, if
              any.  If var_nm does not have an attribute att_nm, there is no effect.

       o      Overwrite.   Write  attribute  att_nm  with  value  att_val  to  variable   var_nm,
              overwriting existing attribute att_nm, if any.  This is the default mode.

       The  value  of att_type is a single character abbreviation ( f, d, l, s, c, or b) standing
       for one of the six primitive netCDF data types:

       f      Float.  Value(s) specified in att_val will  be  stored  as  netCDF  intrinsic  type
              NC_FLOAT.

       d      Double.   Value(s)  specified  in  att_val  will be stored as netCDF intrinsic type
              NC_DOUBLE.

       l      Long.  Value(s) specified in att_val  will  be  stored  as  netCDF  intrinsic  type
              NC_LONG.

       s      Short.   Value(s)  specified  in  att_val  will  be stored as netCDF intrinsic type
              NC_SHORT.

       c      Char.  Value(s) specified in att_val  will  be  stored  as  netCDF  intrinsic  type
              NC_CHAR.

       b      Byte.   Value(s)  specified  in  att_val  will  be  stored as netCDF intrinsic type
              NC_BYTE.  The specification of att_type is optional in Delete mode.

       The value of att_val is what  you  want  to  change  attribute  att_nm  to  contain.   The
       specification  of  att_val  is  optional  in  Delete mode.  Attribute values for all types
       besides NC_CHAR must have an attribute length of at least one.   Thus  att_val  may  be  a
       single value or one-dimensional array of elements of type att_type.  If the att_val is not
       set or is set to empty space, and the att_type is NC_CHAR, e.g., -a units,T,o,c,""  or  -a
       units,T,o,c,,  then  the  corresponding  attribute  is  set  to  have  zero  length.  When
       specifying an array of values, it is safest to enclose att_val in double or single quotes,
       e.g.,  -a  levels,T,o,s,"1,2,3,4"  or  -a levels,T,o,s,'1,2,3,4'.  The quotes are strictly
       unnecessary around att_val except when att_val contains characters which would confuse the
       calling shell, such as spaces, commas, and wildcard characters.

       NCO processing of NC_CHAR attributes is a bit like Perl in that it attempts to do what you
       want by default (but this sometimes causes unexpected results if  you  want  unusual  data
       storage).   If the att_type is NC_CHAR then the argument is interpreted as a string and it
       may contain C-language escape sequences, which NCO will interpret before writing  anything
       to  disk.   NCO  translates  valid  escape sequences and stores the appropriate ASCII code
       instead.  Since two byte escape sequences represent one byte ASCII codes, e.g.,  ASCII  10
       (decimal),  the  stored  string attribute is one byte shorter than the input string length
       for each embedded escape sequence.  These sequences in particular allow convenient editing
       of  formatted  text attributes.  See ncks netCDF Kitchen Sink, for more examples of string
       formatting (with the ncks -s option) with special characters.

       Analogous to printf, other special characters are also allowed  by  ncatted  if  they  are
       "protected"  by  a  backslash.   NCO  simply  strips away the leading backslash from these
       characters before editing the attribute.  No other  characters  require  protection  by  a
       backslash.  Backslashes which precede any other character will not be filtered and will be
       included in the attribute.

       Note that the NUL character which terminates C language strings is assumed and need not be
       explicitly  specified.   If  NUL  is  input,  it  will not be translated (because it would
       terminate the string in an  additional  location).   Because  of  these  context-sensitive
       rules,  if  wish  to  use  an  attribute  of  type NC_CHAR to store data, rather than text
       strings, you should use ncatted with care.

EXAMPLES

       Append the string "Data version 2.0.\n" to the global attribute history:
              ncatted -O -a history,global,a,c,"Data version 2.0\n" in.nc
       Note the use of embedded C language printf()-style escape sequences.

       Change the value of the long_name attribute for variable T from whatever it  currently  is
       to "temperature":
              ncatted -O -a long_name,T,o,c,temperature in.nc

       Delete all existing units attributes:
              ncatted -O -a units,,d,, in.nc
       The  value  of  var_nm  was  left blank in order to select all variables in the file.  The
       values of att_type and att_val were left blank because  they  are  superfluous  in  Delete
       mode.

       Modify all existing units attributes to "meter second-1"
              ncatted -O -a units,,m,c,"meter second-1" in.nc

       Overwrite the quanta attribute of variable energy to an array of four integers.
              ncatted -O -a quanta,energy,o,s,"010,101,111,121" in.nc

       See  the  manual  for  more  complex  examples,  including  how to input C-language escape
       sequences and other special characters like backslashes and question marks.

AUTHOR

       NCO manual pages written by Charlie Zender and originally formatted by Brian Mays.

REPORTING BUGS

       Report bugs to <http://sf.net/bugs/?group_id=3331>.

COPYRIGHT

       Copyright © 1995-2018 Charlie Zender
       This is free software; see the source for copying conditions.  There is NO  warranty;  not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       The  full  documentation  for  NCO  is maintained as a Texinfo manual called the NCO Users
       Guide.  Because NCO is mathematical in nature, the  documentation  includes  TeX-intensive
       portions   not  viewable  on  character-based  displays.   Hence  the  only  complete  and
       authoritative versions of the  NCO  Users  Guide  are  the  PDF  (recommended),  DVI,  and
       Postscript   versions  at  <http://nco.sf.net/nco.pdf>,  <http://nco.sf.net/nco.dvi>,  and
       <http://nco.sf.net/nco.ps>,  respectively.   HTML  and  XML  versions  are  available   at
       <http://nco.sf.net/nco.html> and <http://nco.sf.net/nco.xml>, respectively.

       If the info and NCO programs are properly installed at your site, the command

              info nco

       should give you access to the complete manual, except for the TeX-intensive portions.

       ncap(1),  ncap2(1),  ncatted(1),  ncbo(1),  ncclimo(1),  nces(1),  ncecat(1),  ncflint(1),
       ncks(1), nco(1), ncpdq(1), ncra(1), ncrcat(1), ncremap(1), ncrename(1), ncwa(1)

HOMEPAGE

       The NCO homepage at <http://nco.sf.net> contains more information.

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