# Administrating system-wide Debian packages


## Tools

  * apt - for interactive simple command-line tasks
  * apt-get - for scripted tasks
  * aptitude - for fullscreen browsing and complex tasks


## System upgrade

Make sure your current system is up-to-date.  
Check </etc/apt/sources.list*> files that only current release is used.
Then update and upgrade:

```shell
apt update
apt upgrade
```

Make sure that all auto-installed packages are marked as such.  
Start aptitude in fullscreen mode:

```shell
aptitude -u
```

In aptitude...:

  * Check each installed package: Flag as auto-installed as appropriate
  * Remove no longer used packages as needed (press "g" twice).

Double-check packages unneeded for or alien to current release.  
Compute package lists:

```shell
localbackuppkglists
```

After running the above,
locate and inspect aliens and explicits below </etc/*/localpkglists.*>.