Korn Shell: Unix and Linux Programming Manual, Third Edition, The

Quoting

Quoting is used to prevent the shell from treating characters or words specially. There are three methods of quoting: First, \ quotes the following character, unless it is at the end of a line, in which case both the \ and the newline are stripped. Second, a single quote (‘) quotes everything up to the next single quote (this may span lines). Third, a double quote (“) quotes all characters, except $, ‘ and \, up to the next unquoted double quote. $ and ‘ inside double quotes have their usual meaning (i.e., parameter, command or arithmetic substitution) except no field splitting is carried out on the results of double-quoted substitutions. If a \ inside a double-quoted string is followed by \, $, ‘ or “, it is replaced by the second character; ...