6.9 Quoting

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 ‘!’).