A file or folder is considered hidden if the name starts with a .. Hidden files and folders will not be shown by default by file managers such as GNOME Files or Dolphin, or when listing for files and folders using command line tools such as ls.
Files and folders could set to hidden by prepending a . to its name and could be unhidden by removing the leading .. This is different than it is in Windows as files and folders are visible or hidden based on file/folder attributes rather than the name.
Files and folders could be hidden by renaming it with the pre-prended . using graphical files managers or by using mv command at the terminal.
$ ls temp/ file folder
$ mv temp/file temp/.file
$ ls temp/ folder
$ mv temp/.file temp/file
$ ls temp/ file folder
Comment anonymously. Login not required.