Best resources to learn bash scripting?

I've programmed in a number of languages for two years now, I mean that I know how to design and implement a decent solution for a given problem. However, bash is being a major headache to me, just nothing does work as expected—or even without errors. All of the guides I've found were incredibly informal, not properly summarising its syntax or telling the most common errors you can make. So what can you recommend me?