50 Good to know File Extensions for the Technical Writers

If you are into technical writing, you will often come across or handle different types of files on a daily basis. Some times it is quite cumbersome to save a particular file with all the different types of file extension options to choose from.

In this article, I have compiled the most used file extensions in the technical writing industry. Read to understand:

1. What each file extension acronym stand for
2. Description of the file extensions

What is File Extensions?

A file extension is a unique identifier that describes the file type. 

The file extension is added as a suffix after the filename and it starts with a period, for example, .doc, PDF, .jpeg, etc.

Why file extensions are useful

There is a reason why file extensions are present and following are the ways in which they are useful:

1. File extensions help to categorize the files and tells the file type.
2. In your day-to-day job, you might come across numerous files but only if you know the file type by just looking at the extension it could save time.
3. If you know the distinct purpose of each file extension you can choose the correct one which is supported in multiple applications.
4. When you have a lot of files, sorting them in the order of their file extension would be easier to arrange or manage them.

If you are not able to see the file extension in your windows explorer, you need to enable the file extension to display them.

There are lots of file extensions. You don’t require to know them all. Honestly, it is not possible also. 

Based on our daily computer usage and file handling I have categorized some file extension which you need to know into the following sections:

1. Common or General File Extensions

2. DITA File Extensions

3. Application or Tools Output File Extensions

Did You Know

A file extension with an .adobe is a type of malware utilized by cybercriminals. It is not associated with the software company Adobe Inc. 

.lock is one more example of such extensions.

Common or General File Extensions

These are files that you and I handle almost every day.

Extension	Name	Description
.7Z	7-Zip Compressed File	This are the compressed archive files created with 7-Zip open-source software.
.APK	Android Package File	The file which contains android application files. It can be downloaded and installed on mobile devices.
.APP	macOS Application	The executable files for macOS. This is the .exe counterpart in macOS.
.BAK	Backup File	The backup file the which the application creates automatically when the program overwrites any existing data.
.BAT	DOS-Batch File	The text file contains a sequence of commands for the OS to perform batch processing.
.CRX	Chrome Extension	The crome browser extensions which carries .JS and .JSON files
.EXE	Windows Executable File	This file is used to run and install the computer application software for windows only.
.ICS,   .CAL	Calendar File	The universal calendar file format which can be opened across multiple apps. It  stores the calendar data
.JAR	Java Archive File	This file aggregates multiple JAVA class files and metadata.
.MSG	Outlook Mail Message	MSG is a file extension for the mail message that is used in Microsoft Outlook.
.MSI	Windows Installer Package	MSI files are used by Windows for installation, storage, and removal of programs.
.PKG	Mac OS X Installer Package	This extension is used for several file formats that contain packages of software and other files.
.PLUGIN	Mac OS X Plugin	File extension of mac application plugins used to extend the application.
.RTF	Rich Text Format File	Rich Text Format file extension is a document file format by Microsoft.
.SQL	Structured Query Language Data File	The file which is used to query (add, delete, insert, extract data) the database.
.TMP	Temporary File	File extensions for the temporary files are automatically created to store certain data.
.TTF	TrueType Font File	This is a raster font format used by Apple and Microsoft.
.TXT	Plain Text File	The basic document file format which you generally open with Notepad.
.ZIPX	Extended Zip File	This is the file extension for compressed fike and is the most advanced compressed file.

Did You Know

You can change the file extension by simply renaming the files. 

This is also a way to hide the file as changing the file extension to a random extension prevents it from opening.

DITA File Extensions

Thes are the files that you will find inside the installed directory of any DITA supported authoring tool (such as Oxygen, XMetal, FrameMaker, etc). Knowing the file extension helps in identifying the file types. 

The question that may arise is: why would you look for this kind of file and tamper with DITA? The answer is- Yes! DITA customization.

Extension	Name	Description
.CSS	Cascading Style Sheet	Cascading Style Sheet file used to format the   contents of HTML.
.DITA	Darwin Information Typing Architecture	XML file created in the Darwin Information Typing Architecture (DITA) format
.DITAVAL	DITA Conditions File	This is a conditional processing profile (DITAVAL file) used to identify which values are to be used for conditional processing during publishing.
.LIB	Generic Data Library	This contains a library of information which is used for a particular program.
.XML	Extensible Markup Language	Stores information which is used across many apps. CSS and XSL is applied on XML to generate HTML and PDF outputs  respectively.
.XSD	XML Schema Definition	This file defines the XML schema. In other words, it defines which XML tags and attributes will appear.
.XSL	Extensible Stylesheet Language	Extensible Stylesheet Language file used to format the contents of XML.
XSLT	Extensible Stylesheet Language Transformation	This is a turing completed program used to format the contents of XML.

Application or Tools Output File Extensions

These are various output files from various software/tools.

Extension	Name	Description
.AI	Adobe Illustrator File	Output file for the vector graphics editing program Adobe Illustrator.
.CDR	CorelDRAW Image File	Vector graphics file that stores a digital image encoded and compressed pieces of information. Output file for Corel application.
.COR	CorelDRAW Drawing	The file extension for storing vector images made from CorelDraw.
.DOC	Microsoft Word Document	Word processing document used to display text, images, links, etc
.DOT	Word Document Template	This is a template format supported by multiple word processors.
.FXG	Flash XML Graphics File	This stores the XML-based graphics file format for describing two-dimensional vector graphics. Output for Adobe Flash.
.GDOCX	Google Drive Document Link File	The output file extension for Google docs.
.GDRAW	Google Drive Drawing	This file extension stores the URL to google docs drawing.
.IND,   INDD	Adobe InDesign Document	The output file extension for Adobe InDesign.
.JPG	NA	Image format to store the raster format. Mostly used in digital photography.
.MD	Markdown	A simple text file that dialects the Markdown language. Mostly used to create the readme-files in the software package.
.MIF	FrameMaker Interchange Format File	It is a text file that can be parsed easily by Adobe FrameMaker.
.MML	FrameMaker Maker Markup Language File	The output file extension for Adobe FrameMaker.
.PDF	Portable Document Format File	Word processing document used to display text, images, links, etc
.PNG	Portable Network Graphic	This format is used to store images with high quality, vector images, and images with a transparent background.
.PPT	Microsoft PowerPoint Presentation	Output files for a slide show which stores, text, images, links, etc.
.PUB	Microsoft Publisher Document	This is a file format used for different types of publications like newsletters, flyers, brochures, postcards, etc.
.SGML	Standard Generalized Markup Language File	Very old markup language. Considered to be the parent of XML language.
.SVG	Scalable Vector Graphics File	This file extension is for storing two-dimensional vector graphic format images in form of XML.
.SVGZ	Compressed Scalable Vector Graphics File	Same functionality of SVG with the support of storing transparency, gradients, animations, and filter properties.
.VSDX	Visio Drawing	Microsoft Visio output file that stores shapes, lines, text, and other objects.
.XLS	Microsoft Excel Spreadsheet	Output files can store data in the forms of rows and columns.

Conclusion

In this article, we have compiled the file extension list which are very useful for the technical writers. We have also stated what is the purpose of a file extension and how beneficial it is to know the extension.

Let me know in the comments below, which file extension did you learn today? 

Also, let me know in the comments below if I have missed any file extension which are good to know for technical writers.

If you like this article, please share it.

Thanks for reading.

Cheers 🍻