谁能解释之间有什么区别
echo $"Starting $CMD"
和
echo "String $CMD"
他们似乎看起来是一样的。
Answer 1:
Look up the QUOTING section of the bash man page:
Words of the form
$'string'are treated specially. The word expands to string, with backslash- escaped characters replaced as specified by the ANSI C standard. Backslash escape sequences, if present, are decoded as follows:
- \a alert (bell)
- \b backspace
- \e an escape character
- \f form feed
- \n new line
- \r carriage return
- \t horizontal tab
- \v vertical tab
- \ backslash
- \' single quote
- \nnn the eight-bit character whose value is the octal value nnn (one to three digits)
- \xHH the eight-bit character whose value is the hexadecimal value HH (one or two hex digits)
- \cx a control-x character
The expanded result is single-quoted, as if the dollar sign had not been present.
And note the follow description double quoted strings preceded by $ ($"string"):
A double-quoted string preceded by a dollar sign ($) will cause the string to be translated according to the current locale. If the current locale is C or POSIX, the dollar sign is ignored. If the string is translated and replaced, the replacement is double-quoted.
Answer 2:
$""是引用一个用于语言翻译的一种形式。 如果调用的bash与-D标志将打印出所有这样的字符串。 当语言环境是C或POSIX ，这种形式的报价并没有做任何事情。
这些字符串使用gettext查找合适的翻译。 例如，如果你的脚本有字符串$"Hello, World" ，你已经正确安装MO文件翻译该字符串到，比如说，法国，你可以执行你的脚本是这样的：
LANGUAGE=fr_FR ./yourscript
和期望的所有实例$"Hello, World"是为卓悦输出，招徕世界报 （假设这就是实际上是在你的翻译文件）。
翻译不是魔术或自动的，所以你必须提供与任何翻译字符串它已经没有翻译引擎 。
（PS -我挂导确实提到这个安全漏洞 ，但你可能会错过它，如果你脱脂，所以我强调一遍在这里。）
文章来源: Bash echo with an $ character outside the string
