xrandr swap two displays

#!/usr/bin/bash
xrandr | grep -E '^(VGA|HDMI).* connected' | while read line; do
    port=`echo $line | sed -E 's/([^ ]+) .*/\1/'`
    isLeft=`echo $line | grep -E '\+0\+0'`
    if [[ $isLeft ]]; then
        if [[ $left ]]; then
            right=$left
        fi
        left=$port
    else
        right=$port
    fi
    if [[ $left && $right ]]; then
        xrandr --output $left --right-of $right
    fi
done

#You must connect two displays only (no less, no more).
#They should have same resolution.
#Tips: Set up hot keys.