As far as I know. The POSIX spec[1] simply declares that in single quotes all characters will be preserved exactly, except for single quotes, which aren't allow

As far as I know. The POSIX spec[1] simply declares that in single quotes all characters will be preserved exactly, except for single quotes, which aren't allowed. Likewise, for double quotes, except that it also performs expansions ($) and allows escaping (\). [1]https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V...