Becoming proficient with tools that allow me to pry into running processes and see what they are doing under the lid e.g. lsof to see files and ports opened u

Becoming proficient with tools that allow me to pry into running processes and see what they are doing under the lid e.g. lsof to see files and ports opened up by a process strace to look at what system calls to the Kernel by program is making (and ltrace for library calls) pstree to see subprocesses spawned gdb to inject myself into infinite loops of programs written in c-based implementations (e.g. Ruby) I'm a collector of aha-ish moments so if you want more, my YouTube account is linked to in my profile.