#!/bin/bash

T1=`vtdate -in '2017-05-28 06:00'`
T2=`vtdate -in '2017-05-28 21:30'`

mkdir -p zevsm

T=$T1
while [ $T -le $T2 ]
do
   [ ! -s zevsm/$T ] && {
      vtdate -is $T
      vtread -T$T,+1m /raw | vtmix -c 0.559,0.829,0 | vtnspec -r16.6666e-3 -a -f82 -w3 > zevsm/$T
   }

   T=$((T + 60))
done