#!/bin/sh
r.mapcalc water = 120
d.rast water
i=1
while [ $i != 100 ]
do
    n=1
    while [ $n != 10 ]
        do
            r.mapcalc < water.mapcalc
            d.rast water
            n='expr $n + 1'
        done
        g.copy rast=water,water.$i
        i = 'expr $i + 1'
    done

command > outfile.txt

command < infile.txt

cat infile.txt | command