shell 字符串比较

#!/bin/bash
a="ph"
b="ph"
if["$a" = "$b"];then
  echo "success"
fi

这个代码有问题 。。。提示如下：
./equ.sh: line 4: syntax error near unexpected token `then'
./equ.sh: line 4: `if["hi" = "hi"];then'

[最优解释]
楼主错误的原因是因为if["$a" = "$b"];then中少了空格。不是==的问题。
if [ "$a" = "$b" ]; then这样就行了。
[其他解释]

#!/bin/bash
a="ph"
b="ph"
if["$a" == "$b"];then
  echo "success"
fi

[其他解释]
甚是纠结，求指明方向。。
[其他解释]

#!/bin/bash
a="ph"
b="ph"
if[ "$a" == "$b" ];then
  echo "success"
fi

[其他解释]
xuexileha
[其他解释]
嗯,是的...vi里写程序,空格很重要