Once you learn how Emacs works and how it can be programmed, you can create interactive tools extremely quickly to make lots of tasks you encounter day to day easier. I do this all the time.
Inside Emacs, you can:
- "M-x apropos" to search for commands of interest
- "C-h f" to get documentation for particular functions by name
- "M-x find-function" to jump to the definition of a particular function
- "M-x find-library" to load a library into a buffer so you can read and (depending on your permissions) edit it.
The Elisp reference is very good, and most libraries are well documented. Between that, the ability to jump around the code base, and trying things out in the "scratch" buffer (it's an Elisp REPL disguised as an editing buffer), you should be able to get quite far.
https://www.gnu.org/software/emacs/manual/html_node/eintr/in...
This manual is also the part of the emacs distribution.