Correcting files using NCO utilities (namely: ncatted and ncap2)

changer.sh

#!/bin/bash

folder=.
prefix=ANUSPLIN_latlon_stmn_
var_name=daily_minimum_temperature
for x in ${folder}/${prefix}*.nc
do
    x_name=$(basename $x)
    part=$(echo $x_name | cut -d"." -f 1)
    #get the year and month from the file name
    y=$(echo $part | cut -d"_" -f 4)
    m=$(echo $part | cut -d"_" -f 5)
    #change time units
    ncatted -O -a units,time,m,c,"days since ${y}-${m}-01" $x
    
    # decrement the time values so they start from 0
    ncap2 -O -s "time=time-1;" $x -o $x

    #replace NaNs with a value specified in the missing_value attribute
    ncap2 -O -s "where(${var_name} != ${var_name}){${var_name}=${var_name}@missing_value;}" $x -o $x 
done