Skip Navigation Links www.nws.noaa.gov 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center
 
 

 
About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

 
HOME > Monitoring_and_Data > Oceanic and Atmospheric Data > Reanalysis: Atmospheric Data > wgrib2-d
 

wgrib2: -d

Introduction

The -d N option specifies the grib message number (N) to process. (The -d N option comes from wgrib where "d" stood fom "dump".) If Nth message has submessage, then the first submessage is chosen (N.1). For messages with submessages, use -d N.M to select the Mth submessage of the Nth message. If M is missing, only the first submessage is selected.

With wgrib2 v3.0.0, you can add an optional offset. For example, -d N:OFFSET will skip OFFSET bytes (must be positive), find the next grib message, give it a label N, and dump it. The other form, -d N.M:OFFSET will skip OFFSET bytes (must be positive), find the next grib message and dump the Mth submessage of that grib message. Using the offset option can be faster for large files, and can be used to skip sections of a grib file that stop wgrib2 processing. The -d option works for files and pipes.

If there are more than one -d on a command line, only the last one is used.

The form, -d all, is not valid in wgrib2. This is the default action.

The -d should be used with caution. The order of messages records within grib files can change without notice (ex. today's forecast may have a different order from tomorrow's forecast). I use -d interactively but this option should not be used in scripts unless you are 100% certain of the order of the records.

Usage

-d N
-d N.M
-d N:OFFSET
-d N.M:OFFSET
where N is an integer larger than 0, M is an positive integer, OFFSET is a positive integer

Example

$ wgrib2 test.grb2 -s -d 1 -bin data.bin
1:0:d=2005090200:HGT:1000 mb:60 hour fcst
The above command writes the first record to a binary file data.bin


$ wgrib2 test.grb2 -s -d 287.2 -bin data.bin
287.2:37032193:d=2005090200:VGRD:10 m above ground:60 hour fcst
The above command dumps the second submessage of record 287.

$ cat gfs.t00z.master.grb2f048 | wgrib2 - | head -n 4
1:0:d=2018030400:PRES:mean sea level:48 hour fcst:
2:3565800:d=2018030400:REFC:entire atmosphere:48 hour fcst:
3:4748163:d=2018030400:VIS:surface:48 hour fcst:
4:5462029:d=2018030400:UGRD:planetary boundary layer:48 hour fcst:
$ cat gfs.t00z.master.grb2f048 | wgrib2 - -d 3:4748163
3:4748163:d=2018030400:VIS:surface:48 hour fcst:
$ cat gfs.t00z.master.grb2f048 | wgrib2 - -d 1:4748163
1:4748163:d=2018030400:VIS:surface:48 hour fcst:

Using the offset option on a pipe

See also: -for, -i,


NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5830 University Research Court
College Park, Maryland 20740
Climate Prediction Center Web Team
Page modified: Aug 27, 2014, March 19, 2020
Disclaimer Privacy Policy