如何在单引号字符串中使用变量? [英] How do I use variables in single quoted strings?

问题描述

我只是想知道如何在单引号内回显变量(我正在使用单引号，因为字符串中带有引号).

I am just wondering how I can echo a variable inside single quotes (I am using single quotes as the string has quotation marks in it).

     echo 'test text "here_is_some_test_text_$counter" "output"' >> ${FILE}

任何帮助将不胜感激

推荐答案

变量用双引号引起来，而不用单引号引起来:

Variables are expanded in double quoted strings, but not in single quoted strings:

 $ name=World

 $ echo "Hello $name"
 Hello World

 $ echo 'Hello $name'
 Hello $name

如果您只需切换引号，就可以这样做.

If you can simply switch quotes, do so.

如果您希望坚持使用单引号来避免额外的转义，您可以改为在同一参数中混合使用引号:

If you prefer sticking with single quotes to avoid the additional escaping, you can instead mix and match quotes in the same argument:

 $ echo 'single quoted. '"Double quoted. "'Single quoted again.'
 single quoted. Double quoted. Single quoted again.

 $ echo '"$name" has the value '"$name"
 "$name" has the value World

适用于您的情况:

 echo 'test text "here_is_some_test_text_'"$counter"'" "output"' >> "$FILE"

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