VT vertical scrolling test

vertical-scroll-test.sh

#! /bin/bash

LINES=${LINES:-${1}}

echo -ne "\033[2J" # clear screen
echo -ne "\033[H"  # cursor to home

# fill lines with known pattern (numbers from 1 upwards)
for i in `seq 1 ${LINES}`; do
        echo -n "$i ..."
        if [[ $i -lt ${LINES} ]]; then
                echo
        fi
done

echo -ne "\033[5;15r" # set vertical-scroll margin between 5..15
echo -ne "\033[15;1H" # move cursor to bottom (left) margin

# slowly scroll upwards
for i in `seq 1 5`; do
        sleep 1
        echo -ne "I'm at that line (15;1) for the ${i}. time.\r\n"
done

echo -ne "\033[1;${LINES}r" # reset vertical margin
echo -ne "\033[${LINES};1H" # move cursor to bottom left