A non-quoted backslash ‘\’ is the Bash escape character. It preserves the literal value of the next character that follows, with the exception of newline. If a \newline pair appears, and the backslash itself is not quoted, the \newline is treated as a line continuation (that is, it is removed from the input stream and effectively ignored).
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
\nnn
the eight-bit character whose value is the octal value nnn (one to three digits)
\xHH
the eight-bit character whose value is the hexadecimal value HH (one or two hex digits)
\cx
a control-x character
The expanded result is single-quoted, as if the dollar sign had not been present.
