Q. apt-get と apt コマンドの違いってなに?

A. 質問とその回答が既にあるのでそちらを参照のこと

• What is the difference between apt and apt-get? - Ask Ubuntu

• list: which is similar to dpkg list and can be used with flags like --installed or --upgradable.
• search: works just like apt-cache search but sorted alphabetically.
• show: works like apt-cache show but hide some details that people are less likely to care about (like the hashes). The full record is still available via apt-cache show of course.
• update: just like the regular apt-get update with color output enabled.
• install,remove: adds progress output during the dpkg run.
• upgrade: the same as apt-get upgrade --with-new-pkgs.*
• full-upgrade: a more meaningful name for dist-upgrade.
• edit-sources: edit sources.list using $EDITOR.

Ubuntu Trusty(ver. 14) から使えるようになったとのこと

複数コマンドを使い分けていた部分が集約されていて、 apt のほうが使い易しい