user_installed

#!/usr/bin/env bash
logdir="/var/log/"
installed=""
# Scan all dpkg logs for installed packages
for file in ${logdir}dpkg.log*; do
    if [ ${file##*.} = "gz" ]; then
		installed=$installed`gzip -dc $file | grep ' installed' | cut -d' ' -f5`
	else
		installed=$installed`cat $file | grep ' installed' | cut -d' ' -f5`
	fi
done
# Get all packages installed at the time of OS installation
os_installed=`gzip -dc ${logdir}installer/initial-status.gz | grep 'Package: ' | cut -d' ' -f2`
# Get all automatically installed packages
auto_installed=`apt-mark showauto`
# Concatenate all the installed packages..
all_installed="${installed}${os_installed}${auto_installed}"
# ..and remove all duplicates, which leaves only user installed packages
echo "${all_installed}" | sort | uniq -u