A file extension is a suffix that is added to the end of a file name after a dot. It is usually two to four letters long. File extensions help Windows and other operating systems to know the standard ...

Every file that we have saved on our computers has a particular extension. The file extension is added at the end of the filename followed by a dot (.). It tells the operating systems about the ...

TUAW reader David wrote us to ask how he could view .erb files (Rails development) in Quick Look. The fact is, there are a lot of plain-text files with extensions that Quick Look doesn't recognize. It ...

Tax season 2026 opened on Monday, Jan. 26, and some filers already know they'll need an extension to file. Here's how to get a tax-filing extension.