File names that begin with a dot (.) are called hidden files because they are not displayed unless the special -a option is used.

Use ls -a to list hidden (.) files.

Example

In this example, the user uses the pwd command to check his location in the filesystem:

$ pwd
/home/chuck

Next, the user uses the -a switch with the ls command to list hidden files. Hidden files (files that start with a .) are frequently used to customize a user's work environment.

$ ls -a

.	.mysql_history	books_addconfirm.php.bak	stuff
..	.profile	books_delete.php
.bash_history	.swp	edits.php
.bashrc	books_add.php	play

$