文件擴(kuò)展名是文件名末尾的後綴，用於指示文件類型。它通常位於文件名後的點(diǎn)之後，如.docx或.jpg，幫助計(jì)算機(jī)和用戶識(shí)別如何處理文件。首先，文件擴(kuò)展名告訴操作系統(tǒng)應(yīng)使用哪個(gè)程序打開(kāi)文件，例如.mp3文件由音樂(lè)播放器打開(kāi)，而.xlsx文件由Excel打開(kāi)；其次，它們?cè)诎踩矫嬉埠苤匾?，可幫助識(shí)別偽裝的惡意文件，如document.pdf.exe；常見(jiàn)的擴(kuò)展名包括文檔類的.docx、.pdf，圖像類的.jpg、.png，音頻/視頻類的.mp3、.mp4，代碼類的.js、.py，以及壓縮文件類的.zip、.rar；大多數(shù)應(yīng)用程序都有默認(rèn)擴(kuò)展名，如Photoshop使用.psd，AutoCAD使用.dwg；最後，在Windows中可通過(guò)文件資源管理器的“查看”選項(xiàng)卡顯示擴(kuò)展名，在macOS中則通過(guò)重命名操作查看隱藏的擴(kuò)展名。

A file extension is the suffix at the end of a filename that indicates what type of file it is. It usually comes after a dot — like .docx for Word documents or .jpg for image files. This little tag helps both your computer and you understand how to handle the file.

Why File Extensions Matter

File extensions tell your operating system which program should open a file. For example, .mp3 files are audio files and typically open with music players, while .xlsx files are spreadsheets made in Excel. Without the right extension, your system might not know what to do with the file — or worse, might try opening it with the wrong software.

Another reason they're important is security. Some malicious files disguise themselves by using misleading icons or names, but checking the extension can help you spot something suspicious — like a file named document.pdf.exe , which might look like a PDF but is actually an executable.

Common File Extensions You'll See

You come across file extensions every day, even if you don't always notice them. Here are some common ones grouped by category:

• Documents : .docx , .pdf , .txt , .xlsx , .pptx
• Images : .jpg , .png , .gif , .bmp , .svg
• Audio/Video : .mp3 , .wav , .mp4 , .avi , .mov
• Code/Scripts : .js , .py , .html , .css , .php
• Compressed Files : .zip , .rar , .7z

Most apps create files with their own default extensions. For instance, Photoshop uses .psd , while AutoCAD uses .dwg . Knowing these can help you identify what kind of file you're dealing with before even opening it.

How to Show File Extensions (If They're Hidden)

By default, Windows hides known file extensions. That means a file named report.docx just looks like report . If you want to see full filenames, including extensions, here's how:

• On Windows :

  • Open File Explorer.
  • Go to the "View" tab.
  • Check the box labeled “File name extensions” under “Show/hide” options.

• On macOS , extensions are usually visible. But if one is hidden:

  • Right-click the file > “Rename” > Make sure the extension is visible and editable at the end of the name.

This small change makes it easier to tell what kind of file you're looking at, especially when sorting through downloads or attachments.

It's easy to overlook file extensions because they're small and often hidden, but knowing what they mean can save time and prevent mistakes. Once you get used to paying attention, they become a helpful part of daily computing.基本上就這些。

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