apt install: Note, selecting 'foo' instead of './foo_x.y.z_amd64.deb' - what it means?

Question

I searched the web but could not find an answer to:

why apt install ./*.deb writes Note, selecting x instead of './x_something.deb' e.g Note, selecting 'phantomjs' instead of './phantomjs_2.1.1+dfsg-2_amd64.deb' for packages it installs from local files?

Answer 1

Because apt is passing off info to the back end package database and packages can be marked as "selected for install" etc. This database lists only the package name, which is usually only part of the file name. The ./x_something.deb is a filename reference, not a package name, and the ./ part of it is a relative path reference.

A better real example might be for Google Chrome.

Filename is google-chrome-stable_current_amd64.deb plus whatever path reference you have to it.

Package name is actually google-chrome-stable. The version info (current) and architecture of the build (amd64) aren't needed in the package name - architecture is controlled by other parts of the package management subsystem, and the version number could/will/would change to numeric, and is referenced in the various Release and other index files that the apt family fetches (based on sources.list contents) and parses on apt-get update or apt update

ivan@darkstar:~$ dpkg -l | grep google-chrome
ii  google-chrome-stable  76.0.3809.100-1  amd64  The web browser from Google
ivan@darkstar:~$