apt upgrade

manpage

執行

$ man apt

可以找到一段說明

upgrade (apt-get(8))
    upgrade is used to install available upgrades of all packages currently installed on the system from the
    sources configured via sources.list(5). New packages will be installed if required to statisfy
    dependencies, but existing packages will never be removed. If an upgrade for a package requires the remove
    of an installed package the upgrade for this package isn't performed.

help

執行

$ apt -h

可以找到一段說明

upgrade - upgrade the system by installing/upgrading packages

指令範例

執行

$ sudo apt upgrade

執行

$ sudo apt upgrade -y