linux – 为什么这个字符串的值在bash脚本中正在执行？

为什么此脚本在if语句中执行字符串：

#!/bin/bash
FILES="*"
STRING=''

for f in $FILES
do
  if ["$STRING" = ""]
   then
    echo first
    STRING='hello'
   else
    STRING="$STRING hello"
  fi
done

echo $STRING

用sh script.sh输出时运行它：

first
lesscd.sh: line 7: [hello: command not found
lesscd.sh: line 7: [hello hello: command not found
lesscd.sh: line 7: [hello hello hello: command not found
lesscd.sh: line 7: [hello hello hello hello: command not found
lesscd.sh: line 7: [hello hello hello hello hello: command not found
hello hello hello hello hello hello

附：首次尝试shell脚本
谢谢

解决方法:

您正在尝试执行命令[hello.在之后放置一个空格[因此它将被认定为测试.

for f in $FILES
do
  if [ "$STRING" = "" ]
   then
    echo first
    STRING='hello'
   else
    STRING="$STRING hello"
  fi
done