Introduction

The -ndates_fmt option changes the default format that the -ndates prints the date codes. The default format is written in C as " %s". (The date code is converted into a string, and a blank and the string is printed out.)

The -ndates_fmt option is an initialization option, so it runs prior to the processing of the grib file. The -ndates_fmt option needs to preceed the -ndates option.

Default ndates format is " %s"

$ wgrib2 /dev/null -ndates 201802 1dy 6hr
 2018020100 2018020106 2018020112 2018020118$ 

A list of files on one line

$ wgrib2 /dev/null -ndates_fmt " pgb%s" -ndates 201802 1dy 6hr
 pgb2018020100 pgb2018020106 pgb2018020112 pgb2018020118$ 

A list of files, one file per line

$ wgrib2 /dev/null -ndates_fmt "pgb%s\n" -ndates 201802 1dy 6hr
pgb2018020100
pgb2018020106
pgb2018020112
pgb2018020118
$ 

Making a script to process a list of files

bash-4.1$ wgrib2 /dev/null -ndates_fmt "cp pgb%s ~/data\n" -ndates 201802 1dy 6hr >cmd
bash-4.1$ cat cmd
cp pgb2018020100 ~/data
cp pgb2018020106 ~/data
cp pgb2018020112 ~/data
cp pgb2018020118 ~/data
bash-4.1$ 

The -ndates_fmt option understands three back-slash characters.

   \n gets converted into a new-line character
   \t gets converted into tab character
   \\ gets converted into a back-slash character

   Windows will be addressed later with respect to the end of line termination.

Usage

-ndates_new C_FORMAT
   C_FORMAT is a C-language format which includes a %s to print
   the date code.  The only back slash sequences allowed are \n, \t, and \\.