common file extension

ppt     
pptx        
doc 2003    
docx    2007(new)   
xls Microsoft Excel Spreadsheet(2003)   二进制
xlsx    2007(new)   基于xml
txt 纯文本 
htm     
html        
pdf     
json        
xml     
csv Comma Separated Values File
7z  compressed file 
tar archived file   
tar.gz  压缩的打包文件 
zip 压缩文件    



java    java源码
class   java字节码文件
php php source file
js  javascript
jsp java server page
py  python
c   c or c++
cpp c++
cs  C#
h   c or c++ or objective-c header file
lua Lua
m   objective-c implementation file
pl  perl
sh  bash shell
swift   swift