When you want to browse the disk drive and see what files are stored on it you open a Finder window and it displays them. Or does it? Well, it actually only displays some of the files and it does not show all of them. The reason is that some files on the disk are hidden and Finder ignores them, so a Finder window only actually gives you a partial view of what is on the drive.
There may be a reason why certain file is hidden, for example, it may be for security purposes. It's not a great security feature and it's easy to find and access hidden files as we will see, but it is a simple thing to do and it fools novices. OS X may hide system files that it doesn't want you to tamper with because if you modify the contents then the operating system may not function correctly.
Sometimes you do need to see what is actually on a disk or in a folder. For example, you might want to clean up after removing an application. Deleting the obvious files will often not completely remove it and there are files scattered all over the disk and some of them are hidden. Also you might want to access hidden files to get at features that are not normally available. So there are several reasons why you might want to get a fuller picture of what's on the disk.
The usual way to enable Finder to show hidden files is to use a system tweaking and customisation tool and there are lots of them around, some of them are free too. However, there is no need to use a tweaking tool and showing hidden files is a very simple and surprisingly easy thing to do.
Open a Finder window and go to your Library folder. In Mountain Lion for example, click the Go menu, hold down Option and click Library. Open Preferences (it may be in a different location in Library in old versions of OS X). The Preferences folder is used both by the operating system and the applications you have installed to store configuration settings. Look down the list of files and find com.apple.finder.plist, then double click it.
What happens next depends on what software you have installed. On my Mac with Xcode (a free download from the Apple Mac Store), it opens a nice little editor that enables you to easily modify preferences. If you have Text Wrangler installed, it may open in that, and other apps may be used too. I'll continue with the Xcode editor, but for those that don't have an editor, there is a Terminal command you can use, which I'll give in a minute.
Click the Root entry to expand it and among the items that are listed is one called AppleShowAllFile. You will see that the Class is String and that the Value is FALSE. Double click FALSE and enter TRUE. Select File, Save and then quit the Property List Editor.
Not everyone has a simple Preferences editor installed, so here is an alternative. Open the Applications/Utilities folder and run Terminal. At the command prompt, enter:
defaults write com.apple.Finder AppleShowAllFiles TRUE
This adds an item called AppleShowAllFile to com.apple.Finder and sets the value to TRUE. Changing TRUE to FALSE will reverse the change.
Finder is now set to display all files, including ones that are normally hidden from view. But wait, doesn't Finder look the same? Where are those hidden files? Like most applications, Finder reads the configuration settings in the plist file when it starts up, so you need to restart Finder before you can see the effect. You can either click the Apple menu in the top left-hand corner of the screen and select Restart or simply restart Finder without having to completely shut down.
To do this, click the Apple menu and select Force Quit. Select Finder in the window and click the Relaunch button. After Finder has been restarted you can open a window and see all the hidden files. Try looking in your Home and Documents folder - you'll be surprised at what you see.
If you want to get back to the normal Finder view all you have to do is to reverse the change. View com.apple.finder.plist in the Property List Editor and set the AppleShowAllFile setting back to FALSE. Then restart Finder.
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