This question already has an answer here:
I have a pretty small embedded system that has Linux on it for a project. Theres normally about 47% disk space used when I run df. However every time I start up the system that number gets bigger until it hits 100%.
I can get it back down by using apt-get clean, but I don't even want to update anything. My system is used in a limited capacity thats already working fine with what is on it, I don't want any upgrades of package updates.
How can I disable whatever apt is doing to check for updates and download stuff every time it starts up?