为什么这个带有'while [expr]`的bash脚本不会运行？

Question

当我尝试运行脚本时,我得到"第9行:[2:命令未找到"错误.这是我的第一个bash脚本,所以我是一个完整的初学者.

#!/bin/bash

num1=0
num2=1

count=2


while [$count -le $1]
do
num3='expr $num1+$num2'
num1=$num2
num2=$num3
count='expr $count+1'

done

echo "Fib Num: $num3"

Answer 1

在[和周围添加空格].[是一个命令,所以它必须是一个单独的单词.来自man bash:

test expr
[ expr ]
       Return a status of 0 or 1 depending on  the  evaluation  of  the
       conditional  expression expr.  Each operator and operand must be
       a separate argument.  Expressions are composed of the  primaries
       described  above  under  CONDITIONAL EXPRESSIONS.