CDO

I am trying to use CDO to transform the NARR dataset in various ways. Here is some data

Why doesn't CDO seem to be able to use the metadata provided there in .inv and .ctl files? I cannot select variables by name or by index as reported by gdalinfo. The number of variables does not even correspond to that reported by gdalinfo:

$ cdo showname data/197901/narr-a_221_19790101_0000_000.grb
Warning (cgribexScanTimestep1) : Inconsistent verification time (param=59.131 level=0)
Warning (varDefZaxis) : VCT missing
 var130 var2 var1 var7 var11 var13 var52 var51 var135 var33 var34 var39 var158 var20 var221 var226 var7 var11 var51 var39 var33 var34 va
r153 var178 var158 var135 var1 var134 var11 var13 var85 var144 var160 var85 var207 var86 var223 var65 var238 var66 var11 var51 var17 var
52 var1 var33 var34 var13 var253 var252 var208 var87 var181 var246 var247 var248 var249 var131 var157 var156 var54 var1 var7 var1 var7 v
ar11 var190 var196 var197 var1 var7 var11 var33 var34 var136 var1 var7 var33 var34 var7 var52 var11 var51 var135 var33 var34 var39 var13
2 var157 var156 var1 var84 var59 var61 var202 var63 var99 var235 var234 var143 var142 var141 var140 var121 var122 var155 var229 var57 va
r228 var232 var232 var233 var233 var73 var74 var75 var71 var213 var72 var204 var205 var211 var212 var211 var212 var237 var237 var241 var
241 var244 var245 var244 var245 var242 var243 var242 var243                                                                            
cdo showname: Processed 137 variables ( 0.01s )

whereas gdalinfo shows 423 bands, which corresponds to the contents of the accompanying .inv file that gives names and units, etc. which I expected to show in the above output. Is my best approach to compute a parameter table from the .inv file? Its contents look like this:

1:0:D=1979010100:MSLET:MSL:kpds=130,102,0:anl:winds in grid direction:"Mean sea level pressure (ETA model) [Pa]
2:178480:D=1979010100:PRMSL:MSL:kpds=2,102,0:anl:winds in grid direction:"Pressure reduced to MSL [Pa]
3:356960:D=1979010100:PRES:hybrid lev 1:kpds=1,109,1:anl:winds in grid direction:"Pressure [Pa]
4:464170:D=1979010100:HGT:hybrid lev 1:kpds=7,109,1:anl:winds in grid direction:"Geopotential height [gpm]
5:630772:D=1979010100:TMP:hybrid lev 1:kpds=11,109,1:anl:winds in grid direction:"Temp. [K]
6:773618:D=1979010100:POT:hybrid lev 1:kpds=13,109,1:anl:winds in grid direction:"Potential temp. [K]
. . .

Can anyone shed some light on this? Is it a limitation of CDO's GRB support?

I alluded to this in the forum here the other day.