workspace=$(cat /home/mosaid/.i3/.ws )

case "$workspace" in
    "1" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w1.jpg" ;;
    "2" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w2.jpg" ;;
    "3" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w3.jpg" ;;
    "4" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w4.jpg" ;;
    "5" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w5.jpg" ;;
    "6" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w6.jpg" ;;
    "7" ) feh --bg-scale  "/home/mosaid/.i3/wallpaper/dec/w7.jpg" ;;
    #"8" )
you can take it from here