[newbie] File Types

[michael . thorp]

As I look for programs to install in on my linux box, I have run across several that 
have the extension .tgz.  What are these files?  I know what .tar and .gz files are 
and how to uncompress them, but I haven't been successful with any .tgz file.  Would 
appreciate any help.

Thanks

Mike (τΏ~)