[n]<<[-]word
here-document
delimiter
The shell does not perform parameter and variable expansion, com‐
mand substitution, arithmetic expansion, or pathname expansion on
word.
If any part of word is quoted, the delimiter is the result of quote
removal on word, and the lines in the here-document are not ex‐
panded.
If word is unquoted, the delimiter is word itself, and the
here-document text is treated similarly to a double-quoted string:
all lines of the here-document are subjected to parameter expan‐
sion, command substitution, and arithmetic expansion, the character
sequence \<newline> is treated literally
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is false. Backslash-newline is treated literally only in
<<"EOF" heredocs. In <<EOF heredocs, it is removed
(it's a line continuation).
, and \ must be used to
quote the characters \, $, and `; however, double quote characters
have no special meaning.
If the redirection operator is <<-, then the shell strips all lead‐
ing tab characters from input lines and the line containing delim‐
iter. This allows here-documents within shell scripts to be in‐
dented in a natural fashion.
If the delimiter is not quoted, the \<newline> sequence is treated
as a line continuation: the two lines are joined and the backslash-
newline is removed. This happens while reading the here-document,
before the check for the ending delimiter, so joined lines can form
the end delimiter.
^^^^^^^^^^^^^^^^^^^^^^^
Here the description is correct. Not sure why the explanation
how backslash-newline behaves is repeated twice.
