Alpine Linux has become increasingly important as it’s a popular base linux for Docker containers. One it’s many quirks is it doesn’t use Debian (apt) or RPM (yum) software repositories. Insteak alpine uses a package managment client called
apk, which reads from repositories that are neither debian, nor RPM repositories. Instead an alpine linux repository is based off on an
APKINDEX file, which sounds like it’s a bit of a moving target.
While Docker has, for better or worse, become an important tool that you’ll need to understand if you’re doing most sorts of software development, once you crack the surface you’ll find it hasn’t really freed up from the pedantic fiddliness of linux package managment.