Filed under: Tips and tricks, Education, TUAW Tips
TUAW Tip: The Importance of File Extensions
I teach a lot of computers users who are new to the Mac experience, or who have only ever known Windows. And because
virtually every Windows program names files with extension names already, they have no idea what an extension name is,
or that Windows requires files to have file extensions so it can determine what kind of file it is and with which
program to open it.And so they move over to the Mac and proceed to name files without extension names. Of course some programs like Microsoft Office and the Adobe suite have been written to include file extension names by default, but there are just as many that still adhere to the old Mac way of naming files--without extension names. And so then they go to open their files on their PC (from their flash drive, or maybe they emailed them to themselves), and Windows goes "huh, what's this?" after double-clicking. They're left thinking the file is damaged or that the Mac messed it up somehow, when the problem is simply that it's not named well enough for Windows to understand what it is.
To further compound the situation, Apple has determined that the default way of viewing files in the Finder is to have the file extensions hidden. And so sometimes the file is actually named properly but when the user looks at the file in the Finder, it doesn't show the extension name! And then they get confused and try to rename the file and will sometimes get a warning box (a scary thing for lots of new users) asking them if they're sure they want to change the file name extension.
My point is, it's really a mess. As much as I dislike having to adhere to the stupid three-letter-extension name format imposed by the Windows majority, I've decided that it's just easier to teach people to always name their files with extension names. It won't hurt the Mac to have them, and Windows requires them, so it's the least confusing solution.
I also set all the Macs I control to have the Finder always show file extensions in its preferences. Trivia: this attribute is actually stored in an invisible file called .GlobalPreferences.plist in each user's /Library/Preferences folder.

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Reader Comments (Page 1 of 1)
Jason said 11:12AM on 1-26-2006
But you didn't say 1) a step by step on how to enable showing the file extensions and 2) what the heck you're talking about with the Finder preferences mod and how you change that file you listed.
Details?
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djones said 11:27AM on 1-26-2006
Jason, as the screenshot shows, just go to Preferences in Finder, click the Advanced tab (gear icon), and checkmark "Show all file extensions".
There's no "preferences mod"; he's just telling you what file is changed when you enable that option.
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Gary said 11:49AM on 1-26-2006
The only flaw in this is that by default, Windows hides the extensions. So when user names a file on a Windows machine, they are still calling it what ever they want and not putting in or seeing the extension. However you are correct in that when a Apple file is moved over to Windows without and extension, Windows doesn't know what to do with it, but I am not sure that turning on show extensions is the best way to address the issue.
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Steve M said 12:00PM on 1-26-2006
Yes, file extensions have become one of those necessary evils in life. Unfortunately there aren't any better ways that have appeared for having file meta data which is obvious to the users. Both Windows and Unix have taken to using extensions, albeit that Unix hasn't limited itself to three characters.
I hope some day we can be rid of the system, but I don't see how until we eliminate the concept of proprietary document formats associated with applications.
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Chris Meisenzahl said 12:11PM on 1-26-2006
I'm still a fan of file extensions, even when they aren't explicitly needed.
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xyz3 said 12:27PM on 1-26-2006
I filed a feature request to Apple regarding this in 10.1 to change the user default to "Show all file extensions"
Obviously that request wasn't accepted well.
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Chris Coleman said 1:01PM on 1-26-2006
I used to hate file extensions, but I've decided that life is better with them. Besides, as a guy who makes a lot of web pages, it's absolutely essential to know what the extension on a given file is. Before the Web and before the days of trading files back and forth between different platforms, I really believed that it should be the other way around. Now, we need them.
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am said 3:04PM on 1-26-2006
you raise some good points here. in an ideal world, exentsions wouldn't be necessary. unfortunately, as you imply, even users who use only macs and mac apps that don't rely on extensions need to use extensions so they can email files to their Windows-using friends/associates. So, even though they're not *technically* required 90+% of the time, we're all pretty much stuck with them -- whether we're new users who need to email a jpeg to a friend, or professionals who need to upload stuff to a website. Oh well. Thanks, Microsoft.
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umijin said 6:07PM on 1-26-2006
I like file extensions very much, and the way the mac handles them - when the setting is to show them. Here's why.
I want to name my docs the same thing when they are converted to or saved as different file format. This way, I know that all files with that name represent the same version of information. For example, I'll write my class syllabus in word format, and save a distribution version (for secretaries or to post on the web) as a pdf file. So: Bio101Fall05.doc and Bio101Fall05.pdf - this tells me they are the same version if I have to backtrack.
But Windows is a mess - horrible mess. I have to use Windoze to run a DNA analysis program, and when I bring a text file over saved with an extension, Windoze always puts the .txt extension on the file in addition to any other file name. Furthermore, when I want to save files of different formats in any windows program to the same file name (like .tiff and .jpeg for graphics) it doesn't let me! It will replace files with the same name, regardless of the different extension. So I get alot of messed up names: Image12EditJ and Image12EditT, with no extensions visible. Yes, you can alter whether extensions are visible or not in Windoze finder. However, many applications in Windoze cannot recognize formats of a file unless it has a freaking extension... go figure!
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