bash 尽管代码看起来不错，但字符串比较不起作用

Question

下面是我的简单bash脚本

!/usr/bin/sh
cmd_output=$(ctmcontb -ADD  )
echo below is the hex output of "CONDITION: DATE: added"
echo "CONDITION: DATE: added" | od -xc
echo below is the hex output for the variable cmd_ouput
echo "$cmd_output" | od -xc
echo raw input passed to cmdlet with user arguments inputted and a space added infront
echo " CONDITION: DATE: added" | od -xc
if [ "$cmd_ouput" = " CONDITION: DATE: added" ]; then
        echo successfull ran util
        exit 0
else
        echo error occurred running util
        exit 1
fi

下面是输出

ctmtest1-tctmsv80 [49] job_late.sh ctmtest1 u350932-14 0910
below is the hex output of CONDITION:u350932-14 DATE:0910 added
0000000     434f    4e44    4954    494f    4e3a    7533    3530    3933
           C   O   N   D   I   T   I   O   N   :   u   3   5   0   9   3
0000020     322d    3134    2044    4154    453a    3039    3130    2061
           2   -   1   4       D   A   T   E   :   0   9   1   0       a
0000040     6464    6564    0a00
           d   d   e   d  \n
0000045
below is the hex output for the variable cmd_ouput
0000000     2043    4f4e    4449    5449    4f4e    3a75    3335    3039
               C   O   N   D   I   T   I   O   N   :   u   3   5   0   9
0000020     3332    2d31    3420    4441    5445    3a30    3931    3020
           3   2   -   1   4       D   A   T   E   :   0   9   1   0
0000040     6164    6465    640a
           a   d   d   e   d  \n
0000046
raw input passed to cmdlet with user arguments in putted and a space added in front
0000000     2043    4f4e    4449    5449    4f4e    3a75    3335    3039
               C   O   N   D   I   T   I   O   N   :   u   3   5   0   9
0000020     3332    2d31    3420    4441    5445    3a30    3931    3020
           3   2   -   1   4       D   A   T   E   :   0   9   1   0
0000040     6164    6465    640a
           a   d   d   e   d  \n
0000046
error occurred running util

所以你可以看到字符串比较行

if [ "$cmd_ouput" = " CONDITION: DATE: added" ]; then

似乎没有成功比较字符串，即使它们来自我所看到的相同。

我注意到在原始输入通过 cmdlet 运行后添加了一个 space。所以为了解决这个问题，我基本上在字符串比较中手动添加了一个 space （我不知道最好的方法，但我运行没有想法）

基本上我不确定为什么当字符串相同并且我的 bash 代码看起来正确时字符串比较不起作用？

Answer 1

这个版本似乎可以工作？

这是我的代码。

ctmcontb:

#!/bin/bash
echo " CONDITION: DATE: added"

test2.sh:

#!/bin/bash
cmd_output=$(./ctmcontb -ADD "" "")
expected=" CONDITION: DATE: added"
echo below is the hex output of "CONDITION: DATE: added"
echo "CONDITION: DATE:" | od -xc
echo below is the hex output for the variable cmd_ouput
echo "$cmd_output" | od -xc
echo raw input passed to cmdlet with user arguments inputted and a space added infront
echo "${expected}" | od -xc
if [ "${cmd_ouput}"="${expected}" ]
then
        echo successfull ran util
        exit 0
else
        echo error occurred running util
        exit 1
fi

或者，类似这样的东西，基于 return 代码而不是确切的 returned 字符串，看起来更简单并且与 unix 的其余部分更一致，即使它需要更改ctmcontb程序一点：

ctmcontb

#!/bin/bash
if [[ "" -eq 1 ]]; then
  exit 0
else
  exit 1
fi

test.sh

#!/bin/bash
./ctmcontb ""
result="$?"
if [[ result -eq 0 ]]; then
  echo "Success"
  exit 0
else
  echo "Fail"
  exit 1
fi


$ ./test3.sh 2
Fail
$ ./test3.sh 1
Success
$ ./test3.sh 0
Fail

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