We covered a lot in this series, including:

  • What dotfiles and dot directories are
  • What version management is, and why it matters
  • What shims are
  • What a shebang is
  • What the $PATH variable is, and how it's used
  • How to read and modify UNIX's file permissions
  • What the internal field separator (aka $IFS) is, and what it's useful for
  • How to look up documentation on our machine, using both the man and help commands
  • What a shell is
  • What POSIX is
  • What a "builtin" command is
  • How to find out which shell is your machine's default
  • What a .rc file is
  • What shell options are, and how to set them with the set command
  • Some common shell options (set -e and set -x), and what they do
  • How to write boolean conditions in a shell script using the [ or test command
  • Some useful flags for [ ... ] (such as -n and -f).
  • Double- vs. single-= in a shell script
  • Single-[ ... ] vs. double-[[ ... ]] in a shell script
  • Using the $@ symbol to fetch the list of arguments provided to a script
  • How to iterate over arguments in a shell script, using a for-loop
  • How to write a case statement in Bash
  • What export statements are, and why they're useful
  • The difference between shell variables and environment variables
  • The exec command, how it differs from forking, and when to use each one
  • What a "process" is
  • How to use Github and the repository's git history to figure out *why* the code is the way that it is.

And possibly more, as well. I lost count lol.

I still have more questions!

Such as:

  • What happens inside the child process that gets created by the call to exec at the end of the shim file?
  • We still haven't seen the actual logic which picks the right version number, so it must be happening somewhere else. Where does that live, and how does it work?
  • We only scratched the surface of what can be done in Bash. What are some other Bash-isms that we can learn from the RBENV codebase?

These and more questions will be answered in the upcoming soup-to-nuts walk-through of the RBENV codebase. By the end of the walk-through, we will have learned:

  • how RBENV keeps your Ruby versions separate, organized, and compartmentalized.
  • how RBENV implements the "order of precedence" (`shell > script local > cwd local > global`) mentioned here.
  • how to patch RBENV's behavior using hooks and plugins.
  • how to use common Bash tools like sed, awk, and command substitution

If you like what you've read

Please share it with your friends, on Hacker News, Reddit, etc.