Words of the form $'string' are treated specially. The word expands to string, with backslash-escaped characters replaced as specified by the ANSI C standard. Backslash escape sequences, if present, are decoded as follows:\a
alert (bell)\b
backspace\e\E
an escape character (not ANSI C)\f
form feed\n
newline\r
carriage return\t
horizontal tab\v
vertical tab\\
backslash\'
single quote\"
double quote\?
question mark\nnn
the eight-bit character whose value is the octal value nnn (one to three octal digits)\xHH
the eight-bit character whose value is the hexadecimal value HH (one or two hex digits)\uHHHH
the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value HHHH (one to four hex digits)\UHHHHHHHH
the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value HHHHHHHH (one to eight hex digits)\cx
a control-x character
The expanded result is single-quoted, as if the dollar sign had not been present.