Cannot find .deb archive files when/after apt-get install
 

Why .deb archive files cannot be found when/after installing by apt-get install in order that we keep .deb file for future use ?
Audacious was done but in /var/cache/apt/archives is nothing, how to get it definitely?

I guess deb files are not found because they don't exist. They don't exist because they are not needed. If you want the deb file, obtain it from the web site that contains the repository, or try https://pkgs.org/download/audacious.

I now see that there are options, and the behaviour depends on the tool used to install. This is discussed in an askubuntu thread: https://askubuntu.com/questions/8975...-the-deb-files. Most likely also applicable to Debian?

Packages should be in the cache /var/cache/apt/archives

If they are not, you may run apt-get with the "clean" option or you may have something different configured via apt.conf or /etc/apt.conf.d/

Have a look at your cache settings:

@cynwulf. grep -i cache won't catch

shruggy, thanks - forgot all about that one.

Incidentally, the default behaviours for this differ between apt and apt-get. I suggest that the OP is using apt and thus is not building up a cache?