Hidden file and hidden directory

In computing, a hidden directory or hidden file is a directory (folder) or file which file system utilities do not display by default. They are commonly used for storing user preferences or preserving the state of a utility and are frequently created implicitly by using various utilities. Usually the intent is to not "clutter" the display of the contents of a directory with files the user did not create.

Unix and Unix-like environments

In Unix-like operating systems a file or directory that starts with a period/full stop character (for example: /home/user/.config) is to be treated as hidden, that is the ls command does not display them. Use ls with the flag -a (ls -a) to include them. Midnight Commander shows them by default. The Nautilus file manager also excludes from the display filenames contained in .hidden in each directory (the keyboard shortcut Ctrl-h enables the display of hidden files).

Wildcards on the shell command line will not match dotfiles unless they start with an explicit '.' .

Mac OS X

In addition to the "dotfile" behaviour, files with the "Invisible" attribute are hidden in Finder . This is set using the SetFile command. For example, invoking SetFile -a V jimbo will hide the file "jimbo". An alternate is to use chflags command. chflags nohidden ~/Library/ clears hidden attribute on user's Library folder in Mac OS X 10.7 while SetFile fails with an error.

DOS and MS Windows

In MS-DOS and other DOS systems, file directory entries include a Hidden File attribute which is manipulated using attrib command. Use the command line command dir /ah to display the files with the attribute of hidden.

Abuse

Malicious programs can use this functionality to hide their presence.

External links

• Bellevue Linux Users Group: Hidden files in Unix-like operating systems (via archive.org)
• Computer Hope: Microsoft DOS attrib command