Editing 1301: File Extensions

{{comic
| number    = 1301
| date      = December 9, 2013
| title     = File Extensions
| image     = file_extensions.png
| titletext = I have never been lied to by data in a .txt file which has been hand-aligned.
}}

==Explanation==
Almost all file names end in a period followed by a (generally three-letter) suffix known as a {{w|file extension}}, used to determine the type of content contained in the file. Generally (but not always), a particular extension will only be used by a specific program or small set of programs, making a file's extension a quick indicator of how the file might have been produced.

Because of that last part, and the fact that certain programs will tend to be used by only certain types of people, a file's extension may provide a hint toward how trustworthy the file's content may be.

* {{w|.tex}} files are {{w|TeX}} and {{w|LaTeX}} source files; the aforementioned programs are often and almost exclusively used by academics, especially in mathematics and the hard sciences. .tex means serious business.
* {{w|.pdf}} files are a document format by Adobe, frequently used for publication. Thus, a .pdf file is likely to be some type of final product or polished work.
* {{w|.csv}} files contain a bunch of raw data delimited by commas, and are likely computer-generated (from, say, a scientific experiment).
* {{w|.txt}} files contain only plain text, no "rich text" or anything fancy. They are generally used by programmers for purposes such as README files.
* {{w|.svg}} files are a vector graphics format used a lot for diagrams, such as on Wikipedia.
* {{w|.xls}} and {{w|.xlsx}} are spreadsheets. .xls (.xlsx since 2007) is a proprietary format used by Microsoft Excel as part of the Microsoft Office bundle and .xlsx is an ''Office Open XML'' format created by Microsoft. Anyone with Microsoft Office (very popular among Windows Users) could easily make one of these. The files stereotypically contain a mix of raw data (similar to a .csv) and calculations and plots using that data.
* {{w|.doc}} is another proprietary document format, used by Microsoft Word, also part of the Microsoft Office bundle. A good portion of Windows users have Microsoft Office, and any one of them could easily make one of these (probably why Randall doesn't trust it much).
* {{w|.png}} is a bitmap image format designed for the Internet. It is enjoying wide popularity for providing crisp, full-color images with lossless (invisible) compression. Almost all xkcd comics, this diagram included, use PNG. Self-deprecation, maybe?
* {{w|.ppt}} refers to a Microsoft Office Powerpoint file. Again, anyone with Windows can make one of these, but they are usually used for presentations, not documents. Thus, the information will be arranged differently, possibly to "dumb down" the content. 
* {{w|.jpg}} and {{w|jpeg}} are the same and used as an image format with high compression capabilities, excellent for storing photos, but not so good for many other things. This file format is prone to annoying compression artifacts; storing numerical or textual information in a JPEG file is typically a bad idea. Digital cameras use JPEG compression while the original {{w|Raw image format|.raw}} could be up to hundred times larger. Therefore, you can't trust the content of a JPEG file, because it doesn't contain the original content. Further, there is also the ''possibility'' that [http://www.geek.com/news/updated2-new-virus-embeds-itself-in-jpg-images-549279/ viruses] can get embedded into JPEG files. The extension .jpeg is less trustworthy than .jpg as it does not conform to the three letter rule for file extension suffixes, implying the creator is not very tech-savvy.
* {{w|.gif}} is a bitmap image format capable of short animations. It was once ''the'' Internet image file format until PNG gradually replaced it for many good reasons. It made a comeback in recent years, mostly for silly clips of cats falling into boxes. It's also used in blinking ads claiming that you're the '''[[570|570,000]]th VISITOR!''', and in the online adult industry for both content and marketing. In addition, because it can be animated, people will often make seemingly normal images that then have something pop out and startle you.

The title text refers to some plain text editors, producing simple .txt files, where the human editor and not the application is resposible for aligning the text. Proper indents are one method to improve the text for a human reader on such a plain text file.

==Transcript==
:Trustworthiness of Information by File Extension
:[A bar graph charting this. No units or figures are given, but for ease of comprehension this transcript will arbitrarily designate the highest score as "+100"; subsequent scores are estimates based on the size of their bars.]
::.tex: +100
::.pdf: +89
::.csv: +85
::.txt: +67
::.svg: +65
::.xls/.xlsx: +49
::.doc: +21
::.png: +15
::.ppt: +14
::.jpg: +3
::.jpeg: -8
::.gif: -36

{{comic discussion}}
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