restrain mouse

#!/bin/bash

borderxl=$1
borderyu=$2

borderxr=$3
borderyd=$4

check=0

if [ $borderxl -gt $borderxr ]
then
    check=1
fi

if [ $borderyu -gt $borderyd ]
then
    check=1
fi
if [ $check -ge "1" ]
then
    echo "Make sure the first coordinate pair refers to the upper left corner"
    echo "and the second pair refers to the lower right one."
fi

if [ $check -lt "1" ]
then
    while [ true ]
    do
        check=0
        xpos=`xdotool getmouselocation | awk '{ print $1}'`
        xpos=${xpos:2}
        #xpos=`getcurpos | awk '{ print $1}'`
        ypos=`xdotool getmouselocation | awk '{ print $2}'`
        ypos=${ypos:2}
        #ypos=`getcurpos | awk '{ print $2}'`

        if [ $xpos -gt $borderxr ]
        then
            check=1
            xpos=$borderxr
        fi

        if [ $ypos -gt $borderyd ]
        then
            check=1
            ypos=$borderyd
        fi

        if [ $xpos -lt $borderxl ]
        then
            check=1
            xpos=$borderxl
        fi

        if [ $ypos -lt $borderyu ]
        then
            check=1
            ypos=$borderyu
        fi


        if [ $check -ge "1" ]
        then
            xdotool mousemove $xpos $ypos
        fi
    done
fi