Debian

apt and dpkg ↓

list files in package ↓

dpkg-query -L package
# or if not installed
apt-file list package
apt-cache search string
# alias 'search' in stretchbang

aptitude search '?and(~i, ~Araring-backports)'
# list installed with backport upgrades

aptitude search '~Abackports ?not(~S ~i ~Abackports)'
# list all available backport packages (installed or not)

version ↓

apt-cache policy packname
# or just
apt-cache policy
# some sort of repository status

update / upgrade ↓

sudo apt update && sudo apt dist-upgrade
# alias 'up' in stretchbang

install from backports ↓

sudo apt install -t stretch-backports packname

install with no recommends ↓

sudo apt install --no-install-recommends packname
# only the main dependencies (packages in the Depends field) are installed.

clean stuff ↓

sudo apt autoremove # removes unused deps
sudo apt autoclean  # clears downloaded cache

DontBreakDebian ↓

https://wiki.debian.org/DontBreakDebian

SysInfo ↓

ram ↓

sudo /usr/sbin/dmidecode --type memory

general ↓

inxi -F -c 0