Handle errors in file writing
Parameters:
err must be an Error.(a file error)
filename must be a String.(the filename that was being written)
Synchronously write a string to file
filename must be a String.(the filename to write to)
str must be a String.(the string to write)
cb must be a Function.(callback to run on completion)
Handle errors in file writing
Parameters:
err must be an Error.
(a file error)
filename must be a String.
(the filename that was being written)