APT – Difference Between apt-get -d install & apt-get download

The short version.

apt-get install

installs a new package, automatically resolving and downloading dependent packages. If package is installed then try to upgrade to latest version.

apt-get build-dep

Causes apt-get to install/remove packages in an attempt to satisfy the build dependencies for a source package.

The command sudo apt-get build-dep packagename means to install all dependencies for 'packagename' so that I can build it". So build-dep is an apt-get command just like install, remove, update, etc.

The build-dep command searches the local repositories in the system and install the build dependencies for package. If the package does not exists in the local repository it will return an error code.

For installing matplotlib see To Install matplotlib on Ubuntu

^{Source:ManPage & Ravi Saive}

Not much. apt is a new command that supposed to merge several functions from apt-get and apt-cache into one command. It's still a little rough around the edges but here's the command listing from --help:

Basic commands: 
 list - list packages based on package names
 search - search in package descriptions
 show - show package details

 update - update list of available packages

 install - install packages
 remove  - remove packages

 upgrade - upgrade the system by installing/upgrading packages
 full-upgrade - upgrade the system by removing/installing/upgrading packages

 edit-sources - edit the source information file

The equivalent functions are designed to work in similar ways but it's not a proxy command (it's not calling the old ones - it's a new interface directly onto the Apt libraries) so there may be some edge-case changes.

There are also some obvious omissions (download, policy, etc) that power-users will miss and there are a whole raft of undocumented commands (purge still works but I can't find anything on it).

16.04 Update: A lot of the omissions have now been included but aren't yet documented, nor do they have Bash-completions. It's a shame it's taking this long to implement functionality that already exists in the codebase but oh well. My advice is that if you're used to an apt-{get,cache} command, try it on apt. It might work.

There's also a DIFFERENCES TO APT-GET(8) section in the man apt page that's interesting:

   The apt command is meant to be pleasant for end users and does
   not need to be backward compatible like apt-get(8). Therefore
   some options are different:

   ·   The option DPkgPM::Progress-Fancy is enabled.

   ·   The option APT::Color is enabled.

   ·   A new list command is available similar to dpkg --list.

   ·   The option upgrade has --with-new-pkgs enabled by default.

And if you want Bash-completions, I've had an attempt as writing a completions file for it already. These are included with later Ubuntu installs.