Create and restore apt-package-list
you can use this list for example to install all your apt packages on another machine, for example if you migrage or want to start over on a fresh installation
dpkgsudo --get-selectionsapt-get | awk '$2 == "install" {printinstall $1}'(cat pkglist) > packages.list.save
Restore your apt-packages
xargs -a "packages.list.save" sudo apt-get install
Don't forget to save your /etc/apt/sources.list and /etc/apt/sources.list.d/*, too!