mostly stagnant screen

screen-changer.sh

#!/bin/bash
# made this to test the impact of changing a small part of the whole screen versus script(1) file size
export rows=$(tput lines); export cols=$(tput cols);
while :; do
( exec > .tmp-screen-changer.sh;
for r in $(seq 1 $rows); do
        for i in $(seq 1 $cols); do
                if (( $r == $rows / 2 )); then
                        if (( $i > $cols / 2 - 10 && $i < $cols / 2 + 10 )); then
                                printf '%s' $(head -c 1 <(tr -d -c '[:alpha:]' </dev/urandom))
                        else
                printf '%s' X
                        fi
                else
                        printf '%s' X
                fi
        done
done )
clear
cat .tmp-screen-changer.sh
sleep 0.1
done