string $str = "This is some text";

int $length;

int $fileID;

int $fileID = `fileOpen "C:/FileTesting.txt" "w"`;

// Get the string length

$length = `strLength $str`;

// First write out the string length 

writeInt $fileID $length;

// Then write the string

writeString $fileID $str;

fileClose $fileID;