Imagine you are developing an application which runs on Linux (I'm using Ubuntu) and requires a number of packages to be able to run.
One way would be to just install the packages as needed, but sooner than later, you'll forget which packages are needed. It becomes an even bigger problem when you want to install the same set of packages on your production systems.
Therefor, the approach I take is to keep a file called
packages.list as part of the source repository in which I keep track of the packages I need. It's largely inspired on the
requirements.txt approach often found in Python projects.
The content is simple: one package per line.
# Movie processing ffmpeg # PDF processing mupdf-tools poppler-utils qpdf
Now, it would be very easy to have a single command to use
apt to install / update these packages on any system. Well, here is a command that will do exactly that:
sudo apt install -y $(grep -o ^[^#][[:alnum:]-]* "packages.list")
grep command filters out all invalid lines (e.g. the ones which are commented out) and then uses
apt install to install them on the system.