bash If-else on Mac

Question

为什么这么简单的脚本不起作用？

1 for i in {1..6} 
    2 do 
    3  if[ "$i" -lt "3" ] 
    4  then 
    5   echo "a" 
    6  else 
    7   echo "b" 
    8  fi 
    9 done 

或

1 for i in {1..6} 
    2 do 
    3  if[ "$i" < 3 ] 
    4  then 
    5   echo "a" 
    6  else 
    7   echo "b" 
    8  fi 
    9 done 

错误：

./test.sh: line 4: syntax error near unexpected token `then' 
./test.sh: line 4: ` then' 

Answer 1

你需要if和[之间的空间。