A character may be quoted (that is, made
to stand for itself) by preceding it with a ‘\’.
‘\’ followed by a newline is ignored.
A string enclosed between ‘$'’ and ‘'’ is
processed the same way as the string arguments of the
print builtin, and the resulting string is considered to be
entirely quoted. A literal ‘'’ character can be included in the
string by using the ‘\'’ escape.
All characters enclosed between a pair of single quotes ({No value for `dsq'}) that
is not preceded by a ‘$’ are quoted. A single quote cannot appear
within single quotes unless the option RC_QUOTES is set, in which case
a pair of single quotes are turned into a single quote. For example,
print {No value for `dsq'}{No value for `dsq'}
outputs nothing apart from a newline if RC_QUOTES is not set, but one
single quote if it is set.
Inside double quotes (""), parameter and
command substitution occur, and ‘\’ quotes the characters
‘\’, ‘`’, ‘"’, ‘$’, and the first character
of $histchars (default ‘!’).