스크립트는 입력이 명령이라고 생각합니까?

방금 기본 셸 명령을 실행하는 스크립트를 작성하기 시작했지만 두 번째 함수(유효한 연도와 월을 가져와 이를 cal에 삽입해야 함)가 다음 오류와 함께 반환됩니다.

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

이것이 제가 작업 중인 코드입니다. 답변을 찾았지만 왜 컴파일되지 않는지 모르겠습니다.. 날짜를 명령으로 입력하려는 것이 아닙니다!

#!/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