By default, Nautilus does not display certain system and backup files in folders. This prevents accidental modification or deletion of them, which can impair the operation of your computer, and also reduces clutter in locations such as your Home Folder. Nautilus does not display:
You may hide or show hidden files in a particular folder by selecting View ▸ Show Hidden Files.
To set Nautilus to always show hidden files, see Section 6.12 ― Nautilus Preferences.
To hide a file or folder in Nautilus, either rename the file so its name begins with the period (.) character, or create a text file named .hidden in the same folder, and add its name to it, as in the example below:
filename foldername
You may need to refresh the relevant Nautilus window to see the change: press Ctrl+R.