File ExtensionsFile Extensions

Fred MarshallFred Marshall

Coastal Computers & NetworksCoastal Computers & Networks

BBCC – November 12, 2002BBCC – November 12, 2002

File Names and File ExtensionsFile Names and File Extensions

What are they?What are they?

Why are they?Why are they?

Working with them…..Working with them…..

ExamplesExamples.bmp.bmp something.bmpsomething.bmp image file (windows) image file (windows).doc.doc something.docsomething.doc Word document Word document.exe.exe something.exesomething.exe executable executable

program/applicationprogram/application.gif.gif something.gifsomething.gif image file image file.jpg.jpg something.jpg jpeg image filesomething.jpg jpeg image file.mdb.mdb something.mdbsomething.mdb Access database Access database.pdf.pdf something.pdfsomething.pdf Adobe Acrobat file Adobe Acrobat file.ppt.ppt something.pptsomething.ppt Powerpoint document Powerpoint document.rtf.rtf something.rtfsomething.rtf rich text file rich text file.txt.txt something.txtsomething.txt text document text document.wav.wav something.wavsomething.wav sound file sound file.xls.xls something.xlssomething.xls Excel spreadsheet Excel spreadsheet.zip.zip something.zipsomething.zip compressed file (WinZip or compressed file (WinZip or

……

A A File ExtensionFile Extension is a just a type of is a just a type of SuffixSuffix

HistoryHistory

DOS / Early Windows use “8.3” namesDOS / Early Windows use “8.3” names• Up to eight charactersUp to eight characters• a “dot” “.”a “dot” “.”• Up to three more characters Up to three more characters

tomsboat.txttomsboat.txt

Now, Long File Names are OK:Now, Long File Names are OK:

Toms Boat.txtToms Boat.txt

My Picture.jpeg My Picture.jpeg

What are Extensions Used For?What are Extensions Used For?

They tell the computer what to doThey tell the computer what to do

They help you know what the file isThey help you know what the file is

They help you search for filesThey help you search for files

Starting programs directly 1:Starting programs directly 1:

Double click on a program iconDouble click on a program icon If the icon shortcut points to an .exeIf the icon shortcut points to an .exe

• then the computer knows to Execute the then the computer knows to Execute the file – that is, start running the program file – that is, start running the program that’s in that file.that’s in that file.

Starting programs directly 2:Starting programs directly 2:

Double click on an .exe file name in a Double click on an .exe file name in a directory.directory.

Since it’s an .exe file, then the Since it’s an .exe file, then the

computer knows to Execute the file – computer knows to Execute the file – that is, start running the program that is, start running the program that’s in that file.that’s in that file.

Start a program Start a program indirectlyindirectly 1: 1:

Double click on a data / document Double click on a data / document file like:file like:

phones.txtphones.txt

homework.dochomework.doc

Sally.jpgSally.jpg

checking.xlschecking.xls

The computer will start up a program The computer will start up a program that will open the data file.that will open the data file.

Starting programs indirectly 2:Starting programs indirectly 2:

Click on Start / RunClick on Start / Run Type the file name in the box Type the file name in the box even without the extension it will even without the extension it will

start the program with that file namestart the program with that file name• (if there is an .exe or .com file or .txt (if there is an .exe or .com file or .txt

with that name)with that name)

Starting a program indirectlyStarting a program indirectly

How does it do that?How does it do that?• It looks at the file name It looks at the file name extensionextension and and

decides which program is appropriate.decides which program is appropriate. Implications?Implications?

• It can only decide on one program to It can only decide on one program to open based on the file open based on the file extension.extension.

• It can’t read your mind!It can’t read your mind!• Do you want Paint or PrintShop or Do you want Paint or PrintShop or

Photoshop or ……..?Photoshop or ……..?

It can only choose one programIt can only choose one program

So, if you have Paint, Print Shop, So, if you have Paint, Print Shop, Photoshop, Internet Explorer, Photoshop, Internet Explorer, Windows Picture and Fax Viewer, Windows Picture and Fax Viewer, Windows Media Player, etc. etc. …. Windows Media Player, etc. etc. …. they are all capable of opening, for they are all capable of opening, for example, .jpg picture files.example, .jpg picture files.

Which one does it choose?Which one does it choose?

Start a program Start a program indirectlyindirectly 1: 1:

A Nice Trick……A Nice Trick…… Make a Shortcut for the file itselfMake a Shortcut for the file itself Put it on the desktop or… whereverPut it on the desktop or… wherever When you double click on the icon, When you double click on the icon,

the computer willthe computer will• Start the programStart the program• Open the file in that programOpen the file in that program

Example: put reminders on the Example: put reminders on the desktopdesktop

File “Associations”File “Associations”

Windows chooses the program that is Windows chooses the program that is set up in set up in File AssociationsFile Associations

This list This list AssociatesAssociates a file name a file name extension with a particular programextension with a particular program

The Association can be changed (The Association can be changed (but but really need not be changed really need not be changed unless you have a very annoying unless you have a very annoying situationsituation))

That’s too hard! That’s too hard! What else can I do?What else can I do?

Controlling which program will open Controlling which program will open the filethe file

Controlling which program will Controlling which program will open the file 1:open the file 1:

(you do this all the time!)(you do this all the time!) Start the program you want to use – Start the program you want to use –

this has to happen anyway….this has to happen anyway…. Select File / OpenSelect File / Open Find the file you want to Open and Find the file you want to Open and

proceed to Open itproceed to Open it

Controlling which program will Controlling which program will open the file 2:open the file 2:

(works on ME and XP, not on NT)(works on ME and XP, not on NT) Using My Computer or Windows Using My Computer or Windows

Explorer, find the file you want to Explorer, find the file you want to open.open.

Select / highlight the fileSelect / highlight the file Right click on the file – you will get a Right click on the file – you will get a

menumenu Select Select Open WithOpen With

SummarySummary

File extensions help you and the File extensions help you and the computercomputer

Often, automatic actions are niceOften, automatic actions are nice Sometimes, automatic actions are Sometimes, automatic actions are

annoyingannoying You can control what it doesYou can control what it does

RecommendationRecommendation

Make the file extensions visibleMake the file extensions visible

Fred MarshallFred MarshallCoastal Computers & NetworksCoastal Computers & Networks

Ilwaco, WAIlwaco, WA(360) 642-2073(360) 642-2073