Files and folders with names beginning with a dot [.] are hidden or invisible in Linux. They are by default not shown when listing the directory content using the ls command.

To view the hidden files and folders, simply add the -a (or –all) option to the ls command, as in the following example;

$ ls
file  folder
$ ls -a
.  ..  file  folder  .hiddenfile  .hiddenfolder

Do note that the command also display the files . and .. . These are files referring to the current and parent directory respectively, and they exist in every single folder in the system.