dset ^mon_olr_1998.grads 
undef 340282346638528860000000000000000000000.000000 
title CERES/TRMM TOA Upward Longwave Flux (OLR)
format yrev
XDEF  144 LINEAR   1.25  2.5
YDEF  72  LINEAR  -88.75 2.5
zdef     1 levels 1 1 
tdef 8  linear     JAN1998      1mo
vars    1
olr        1 212,8,0 TOA ULWRF (W/m**2)                   
endvars
* title:olr: CERES/TRMM TOA All-Sky OLR $_month $_year