Before you get into those, it’s worth writing down your investment goals. What generally are you trying to accomplish? When you start reading more about investment, some people are going to try to push you into day trading. Obviously investing itself is not guaranteed, it’s a kind of gambling, but all of the short-term stuff is particularly close to casino gambling. Be careful of that.

Some time after I went OpenBSD and then FreeBSD nerd.

qpdf is handy for merging PDFs. Command line but quick to learn for most usage.