The backslash suppresses the special meaning of the character it precedes, and turns it into an ordinary character. To insert a backslash into your regular expression pattern, use a double backslash ('\\').

What does backslash mean in regular expression?

When regular expressions sees a backslash, it knows that it should interpret the next character literally. A regular expression to match the IP address 0.0.0.0 would be: 0\.0\.0\.0. Use the backslash to escape any special character and interpret it literally; for example: \\ (escapes the backslash)

What does \\ mean in regex?

\\ is technically one backslash, but you gotta type two because it's in a string. It's escaping the . . \\' matches the end of a string, but $ can also match the end of a line. The difference might be relevant if you have newlines in a string.