linux – 在字符串外面加上$字符的Bash echo

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.

请注意以下说明双引号字符串前面带$($“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.