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bash 转义引号

tag-icon • tag-icon bash scripting quoting escape-characters
bash 转义引号

我面临一个有趣的挑战，如何在 bash 脚本中转义引号。

我的 bash 脚本有一个很长的 curl 调用，并传递了一个大的 -d json 结构。

#!/bin/bash

Value4Variable=Value4

curl -s -X POST -H "Content-Type: application/json" -H "Accept: application/json" -d  \
'{"Variable1":"Value1", 
"Variable2":"Value2\'s",  # escape of quote doesnt work because of the previous single quote and backslash
"Variable3":"Value3",
"Variable4":"'"$Value4Variable"'", 
"Variable5":"Value5"
}' \
https://www.hashemian.com/tools/form-post-tester.php

在 json 结构中添加单引号的最佳方法是什么？我尝试过各种组合但没有成功。

答案1

有多种方法可以使用不同的引号转义长字符串。最简单的是结束单引号并转义单引号：

'...'\''...'

但您可以做一些更好的事情。 Heredocs 是避免引用问题的好方法：

curl -s -X POST https://www.hashemian.com/tools/form-post-tester.php \
    -H "Content-Type: application/json" \
    -H "Accept: application/json" \
    -d  @- <<EOF
{
    "Variable1":"Value1", 
    "Variable2":"Value2's",
    "Variable3":"Value3",
    "Variable4":"$Value4Variable", 
    "Variable5":"Value5"
}
EOF

@-告诉curl从stdin读取并<<EOF启动heredoc，它将被输入到curl的stdin中。 Heredoc 的好处是，您不需要转义任何引号，并且可以在其中使用 bash 变量，从而避免了担心如何转义引号的需要，并使整个事情更具可读性。

答案2

我将使用--data @filename符号从文件中读取数据：

样本json-data-file内容：

{"Variable1":"Value1", 
"Variable2":"Value2's",
"Variable3":"Value3",
"Variable4":"'$Value4Variable'", 
"Variable5":"Value5"
}

请求：

Value4Variable="Value4"
curl -X POST -H "Content-Type: application/json" -H "Accept: application/json" \
-d @<(sed "s/\$Value4Variable/$Value4Variable/" json-data-file) \
https://www.hashemian.com/tools/form-post-tester.php/test123

输出：

The POSTed value is:

********************

{"Variable1":"Value1", "Variable2":"Value2's","Variable3":"Value3","Variable4":"'Value4'", "Variable5":"Value5"}

********************

Results saved to: test123
*Note: Results are purged periodically. 1 hr minimum life.

答案3

考虑使用 JSON 感知工具来创建 JSON 文档。这样做将消除手动转义特殊字符（如制表符、换行符、双引号等）的需要。单引号实际上是一个字符不需要在 JSON 中转义。您只需要确保 shell 使用正确的引号即可正确识别您的字符串。

工具jo​从这里旨在使从命令行创建 JSON 文档变得非常简单：

somevariable2='line1
line2
line3'

curl -s -X POST \
    -H 'Content-Type: application/json' \
    -H 'Accept: application/json' \
    -d "$( jo \
        variable1="Value1" \
        variable2="$somevariable2" \
        variable3='String with "quotes"' \
        variable4="It's raining!" \
        variable5='\/\/\/\/\/' )" \
    'https://www.hashemian.com/tools/form-post-tester.php'

或者

somevariable2='line1
line2
line3'

jo \
    variable1="Value1" \
    variable2="$somevariable2" \
    variable3='String with "quotes"' \
    variable4="It's raining!" \
    variable5='\/\/\/\/\/' |
curl -s -X POST \
    -H 'Content-Type: application/json' \
    -H 'Accept: application/json' \
    -d @- \
    'https://www.hashemian.com/tools/form-post-tester.php'

任意一段代码的响应是

The POSTed value is:

********************

{"variable1":"Value1","variable2":"line1\nline2\nline3","variable3":"String with \"quotes\"","variable4":"It's raining!","variable5":"/\\/\\/\\/\\/"}

********************

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