Você pode procurar em /var/log/apt/history.log, embora seja necessário verificar os arquivos também.
Parece que synaptic e apt-get fornecem o método
Start-Date: 2012-07-17 11:47:00
**Commandline: apt-get install** unetbootin
Install: unetbootin-translations:amd64 (575-1, automatic), extlinux:amd64 (4.05+dfsg-6, automatic), syslinux-themes-debian:amd64 (11-1, automatic), syslinux-themes-debian-wheezy:amd64 (11-1, automatic), unetbootin:amd64 (575-1), p7zip-full:amd64 (9.20.1~dfsg.1-4, automatic)
End-Date: 2012-07-17 11:47:18
Start-Date: 2012-07-17 11:57:51
**Commandline: /usr/sbin/synaptic**
Install: libunity-protocol-private0:amd64 (5.92.0-0ubuntu1, automatic)
Upgrade: libunity9:amd64 (5.12.0-0ubuntu2, 5.92.0-0ubuntu1), gir1.2-unity-5.0:amd64 (5.12.0-0ubuntu2, 5.92.0-0ubuntu1)
End-Date: 2012-07-17 11:58:09
Aptidão parece não mostrar como
Start-Date: 2012-07-17 15:11:45
Install: 2ping:amd64 (2.0-1)
End-Date: 2012-07-17 15:11:53