When i write the text
set aSecondString to replaceString(aSecondString, "\\", "\\\\")
to a file (plain text, utf-8), it results in a file containing
set aSecondString to replaceString(aSecondString, "\", "\\")
Saving the same text with BBEdit or TextEditor is ok. Am I missing something?
By default, Keyboard Maestro processes text tokens in text fields, so it's interpreting "\\" as "the user wants an actual backslash, as they've escaped it." (Note: This may be far off from the technically correct description of what's going on, but it's how I think of it and remember it :).)
You just need to disable token processing for that action, using the gear menu:
You should then get what you expect in the output file.
Thank you very much!
Ironically, so does the forum, so when you wrote quote backslash backslash quote it helpfully displayed only one of them! I added two more backslashes to your post so it properly displays both of them, hope that's ok 
Hehe, whoops!
-rob.
