#!/bin/bash
for N in -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160 180
do
sed -e 's/minimum/'$N'/g' umbrella.in > input.in
 $AMBERHOME/exe/sander -O -i input.in -o btn_$N.out -p btn.top -c btn.crd -r btn_$N.xyz -x btn_$N.trj
done

This code changed by the author

#!/bin/tcsh
set number=(-180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160 180)
foreach N ($number)
 sed -e 's/minimum/'$N'/g' umbrella.in > input.in
 $AMBERHOME/exe/sander -O -i input.in -o btn_$N.out -p btn.top -c btn.crd -r btn_$N.xyz -x btn_$N.trj
end

This code from dxli75.blog.163.com/blog/static/10676828920101187755227/