How do I escape a backslash in the following regex c# -

here function, i'm trying replace string in file, c# tells me regex malformed. ideas?

public void function(string filename, string path) {     string pathtoammend = @"$serverroot\pathpath";     string newpath = @"$serverroot\" + path;      file.writealltext(filename, regex.replace(file.readalltext(filename), pathtoammend, newpath));                 .... } 

it works if change strings to:

string pathtoammend = @"$serverroot\\pathpath"; string newpath = @"$serverroot\\" + path; 

but have 2 slashes , want 1 slash.

a \ special escaping character in regular expressions. have escape interpreted literal \ , not escape sequence. $ special character (an end anchor), you'll want escape well.

string pathtoammend = @"\$serverroot\\pathpath"; 

using @ create verbatim string means don't have escape \ sake of c# compiler. still have escape \ in regular expression pattern. without verbatim string be:

string pathtoammend = "\\$serverroot\\\\pathpath"; 

of course, jon skeet points out, simple, regular expressions aren't best way go here.