How to List Packages Added/Installed in Ubuntu Debian-based System

dpkg -l

dpkg -l pattern

dpkg --list pattern

dpkg -l |awk '/^[hi]i/{print $2}'

dpkg -l | grep '^ii '

dpkg-query -l | less

dpkg-query -l | grep ansible

dpkg --get-selections

dpkg --get-selections | grep -v deinstall

dpkg --get-selections | grep ansible

dpkg --get-selections | grep -w "install" 

dpkg --get-selections | grep -w "install" | cut -f1 

apt list

apt list pattern

apt list -a sudo

apt list --installed

apt list --installed pattern

apt list --installed | grep ansible

apt list --installed | awk '{split($0, a, "/"); print a[1]}'

apt list --manual-installed=true

apt-mark showmanual

apt show '~i' -a

apt-cache pkgnames

apt-cache policy <package_name>

apt-cache policy ansible

zgrep " installed " /var/log/dpkg.log*

grep " install " /var/log/apt/history.log

cat /var/lib/apt/lists/ppa.launchpad.net_*_Packages | grep '^Package:'

awk '/^Package: / {print $2}' /var/lib/apt/lists/ppa.launchpad.net_*_Packages | sort -u

grep Package /var/lib/apt/lists/ppa.launchpad.net_*_Packages

grep -h -P -o "^Package: \K.*" /var/lib/apt/lists/ppa.launchpad.net_*_Packages | sort -u

grep ^Package /var/lib/apt/lists/ppa.launchpad.net_*_Packages | awk '{print $2}' | sort | uniq

grep ^Package /var/lib/apt/lists/ppa.launchpad.net_*_Packages | awk '{print $2}' | sort -u

grep ' installed ' /var/log/dpkg.log /var/log/dpkg.log.1 | awk '{print $5}' | sort -u

#Intentionally Installed

(zcat $(ls -tr /var/log/apt/history.log*.gz); cat /var/log/apt/history.log) 2>/dev/null | egrep '^(Start-Date:|Commandline:)' | grep -v aptdaemon | egrep '^Commandline:'

(zcat $(ls -tr /var/log/apt/history.log*.gz); cat /var/log/apt/history.log) 2>/dev/null | egrep '^(Start-Date:|Commandline:)' | grep -v aptdaemon | egrep -B1 '^Commandline:'

zgrep -hE '^(Start-Date:|Commandline:)' $(ls -tr /var/log/apt/history.log ) | egrep -v 'aptdaemon|upgrade' | egrep -B1 '^Commandline:'

#sudo apt install dctrl-tools

grep-dctrl -sPackage . /var/lib/apt/lists/ppa.launchpad.net_*_Packages

grep-status -FStatus -sPackage -n   "install ok installed"

#sudo apt install aptitude

aptitude search '~i!~M'

aptitude search -F "%p %V %v" "?narrow(?installed,?not(?archive(stable)))" | grep ansible

#To exclude just stable you need to anchor the regex pattern:

aptitude search -F "%p %V %v %t" '?any-version(?installed ?not(?archive("^stable$")))'

#To exclude multiple repositories:

aptitude search -F "%p %V %v %t" '?any-version(?installed ?not(?archive("^(xenial|xenial-updates)$")))'

#count

sudo dpkg-query -f '${binary:Package}\n' -W | wc -l

#ppa-purge

apt install ppa-purge

Then get ppa list by tab-completion

ppa-purge -o (hit Tab key twice)