Use seq to generate the list of times, instead of a bash for-loop (NO…

…AA-EMC#2264)

I'm running a year-long forecast, which means I get a large portion of the log file dedicated to these loops.  

`seq ${START} ${STEP} ${STOP}` will generate a sequence going from START to STOP by STEP, including STOP if relevant.  That seems to be the purpose of these loops.  It will by default separate the list with newlines, but `seq -s ' ' ${START} ${STEP} ${STOP}` will separate them with spaces instead, more closely mimicing the previous behavior.

I would like this to be two lines in the log, rather than a few hundred, and this may also be faster, though probably more for reasons of fewer writes to disk than because bash isn't designed for arithmetic.

ush/forecast_predet.sh

@@ -117,15 +117,10 @@ FV3_predet(){
   FV3_OUTPUT_FH=""
   local fhr=${FHMIN}
   if (( FHOUT_HF > 0 && FHMAX_HF > 0 )); then
-    for (( fh = FHMIN; fh < FHMAX_HF; fh = fh + FHOUT_HF )); do
-      FV3_OUTPUT_FH="${FV3_OUTPUT_FH} ${fh}"
-    done
+    FV3_OUTPUT_FH="${FV3_OUTPUT_FH} $(seq -s ' ' "${FHMIN}" "${FHOUT_HF}" "${FHMAX_HF}")"
     fhr=${FHMAX_HF}
   fi
-  for (( fh = fhr; fh <= FHMAX; fh = fh + FHOUT )); do
-    FV3_OUTPUT_FH="${FV3_OUTPUT_FH} ${fh}"
-  done
-
+  FV3_OUTPUT_FH="${FV3_OUTPUT_FH} $(seq -s ' ' "${fhr}" "${FHOUT}" "${FHMAX}")"
 
   # Model resolution specific parameters
   DELTIM=${DELTIM:-225}