扩展名为tgz的是用什么压缩的，用何解压？

rt

.tgz suffix is a usual abbreviation of the .tar.gz suffix.  For those who still have no clue, it is gzipped tar archive file.

# tar -zxf *.tgz
should be able to decompress it.

tgz是跟tar.gz是一样的。

可以肯定，是不一样的，因为我在命令行下可以解开，但是用File Roller却不可以打开。

你试过把后缀改成.tar.gz再打开没有？

I agree with dalin:  .tgz should be the same as .tar.gz -- though in Linux the suffix is not mandatory, you can name a file with any extension you want, as long as you know what the file is and treat it properly.  I can rename a file foo.tar.gz to foo.txt -- though it is not a text file, and I can not open it with a text editor. But actually nothing changes, I can still decompress it with tar -zxf foo.txt.

However some other applications use these suffix extensions.  I do not know what a ``file roller'' excatly is, but I am assuming it use some MIME type.  It may not be able to recognize .tgz suffix because the related MIME type say nothing to this suffix.  So the solution should be:  fix your application.