Saved a file in the wrong location and I cannot retrieve it
Solution 1:
You need to use two back slashes. In the terminal using the bash shell (which it is by default) the backslash character tells bash to allow you to continue typing commands on a new line (hence the prompt you saw).
So if you do ls -la \\ that should show you the contents of "\"
Likewise mv \\ fixed should rename the folder to "fixed"