スクリプトは入力がコマンドだと思いますか？

私は基本的なシェルコマンドを実行するスクリプトの作成を始めましたが、2番目の関数（有効な年と月を取得し、それをcalに挿入する必要があります）が次のエラーで返されます。

Enter the year:
2014
/home/duncan/menuscript.sh: line 34: [2014: command not found
/home/duncan/menuscript.sh: line 34: [2014: command not found
This is an invalid year

これが私が作業しているコードです。答えが見つかりましたが、なぜコンパイルされないのかわかりません。

#!/bin/bash
echo "Welcome to Duncan's main menu"
function press_enter
{
    echo ""
    echo -n "Press Enter to continue"
    read
    clear
}
year=
month=
selection=
until [ "$selection" = "9" ] 
do
  clear
  echo ""
  echo "    1 -- Display users currently logged in"
  echo "    2 -- Display a calendar for a specific month and year"
  echo "    3 -- Display the current directory path"
  echo "    4 -- Change directory"
  echo "    5 -- Long listing of visible files in the current directory"
  echo "    6 -- Display current time and date and calendar"
  echo "    7 -- Start the vi editor"
  echo "    8 -- Email a file to a user"
  echo "    9 -- Quit"
  echo ""
  echo "Make your selection:"
  read selection
  echo ""
  case $selection in
    1) who ; press_enter ;;
    2) echo "Enter the year:" ;
       read year ;
       if [$year>1] || [$year<9999]; then
         echo "Enter the month:" 
         read month
         if [0<$month<12]; then
           cal -d $year-$month 
           press_enter
         else
           echo "This is an invalid month"
           press_enter
         fi
       else
          echo "This is an invalid year"
          press_enter 
       fi ;;

    9) exit ;;
    *) echo "Please enter a valid option" ; press_enter ;;
   esac
done