bash中的$'\\ n'是什么意思？

Question

An answer in this stackoverflow question In a Linux shell how can I process each line of a multiline string? mentions that $'\\n' is a special syntax "is not available in every shell".

I wonder what does the syntax mean?

Thank you.

Answer 1

See 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:

...
              \n     new line
...

   The  expanded result is single-quoted, as if the dollar sign had not been
   present.

This syntax is not part of the standard Unix Bourne shell. It may be specific to bash, although I haven't looked around to see if other shells support it.