tar 解压文件

You cannot "install" a .tar.gz file or .tar.bz2 file. .tar.gz files are gzip-compressed tarballs, compressed archives like .zip files. .bz2 files are compressed with bzip2. You can extract .tar.gz files using:

tar xzf file.tar.gz

Similarly you can extract .tar.bz2 files with

tar xjf file.tar.bz2

If you would like to see the files being extracted during unpacking, add v:

tar xzvf file.tar.gz

Even if you have no Internet connection, you can still use Ubuntu's package management system, just download the .deb files from http://packages.ubuntu.com/. Do not forget to download dependencies too.

For an easier way to install packages offline, see the question How can I install software offline?.