Package Manager
Ubuntu
APT
[ https://askubuntu.com/questions/2389/how-to-list-manually-installed-packages List Packages installed by user]
apt-mark
comm -23 <(apt-mark showmanual | sort -u) <(gzip -dc /var/log/installer/initial-status.gz | sed -n 's/^Package: //p' | sort -u)
aptitude
comm -23 <(aptitude search '~i !~M' -F '%p' | sed "s/ *$//" | sort -u) <(gzip -dc /var/log/installer/initial-status.gz | sed -n 's/^Package: //p' | sort -u)