brightness

    #!/bin/bash

    error="Usage: $0 up | $0 down"
    xbl=`xbacklight`
    limite1=2
    limite2=10
    limite3=40
    limite4=100

    if [ "$#" -eq 1 ]
        then
        if [ $1 = "up" ]
            then
            # Augmenter le rétroéclairage
            if [ $(echo "$xbl == $limite4"|bc) -eq 1 ]
                    then
                    echo "Rétroéclairage au maximum !"
                    xbacklight = 100
                else
                if [ $(echo "$xbl < $limite2"|bc) -eq 1 ]
                        then
                        xbacklight +1
                    else
                    if [ $(echo "$xbl < $limite3"|bc) -eq 1 ]
                            then
                            xbacklight +10
                        else
                        xbacklight +20
                    fi
                fi
            fi
        elif [ $1 = "down" ]
            then
            # Diminuer le rétroéclairage
            if [ $(echo "$xbl < $limite1"|bc) -eq 1 ]
                    then
                    echo "Rétroéclairage au minimum !"
                    xbacklight =1
                else
                if [ $(echo "$xbl < $limite2"|bc) -eq 1 ]
                        then
                        xbacklight -1
                    else
                    if [ $(echo "$xbl < $limite3"|bc) -eq 1 ]
                            then
                            xbacklight -10
                        else
                        xbacklight -20
                    fi
                fi
            fi
            else
            echo $error
        fi
        else
        echo $error
    fi
    exit