RVM 2.0: Convert 20,000 lines of shell script into Ruby [Fundraiser]

I used to think that way too. It's so simple. Why don't people spend a little time to learn their tools? It's not that complicated!

Then, over the years, I realized that that's the wrong attitude. You shouldn't expect users to learn stuff no matter how much you think they should. They already have enough other stuff to worry about. They already have their hands full learning other stuff. And the reason why I thought it was easy, was because I already knew it. Expecting other people to go out of their way to learn the things you know is disrespecting their time.

Therefore, software should be easy to use for new users. Software should have a learning curve that's as low as possible. Software should not expect people to learn things that you think is important.

I am very firmly in the pro-usability camp, even for developer tools.

You said that rbenv isn't advanced shell scripting. You are right, it isn't - for us. However, that doesn't mean that it can be utterly confusing for a lot of people. The concept of environment variables are easy, until you get to the common edge cases. Did you know that environment variables are inherited on a per-process basis, so changing them in your shell does not affect already-running processes, and doesn't affect cron? Did you know adding environment variables to bashrc has no effect on cron, init scripts and the like? Lots and lots of people don't realize that. Do you want those people to give up in frustration? I'd say no. I'd say we should help those people with good documentation, and software that just works.

For example, at the Phusion Passenger mailing list, we regularly get questions from people asking why they get "command not found" errors. Apparently a lot of people don't understand what PATH is, or what environment variables are, or that sudo resets them. So we ended up writing this: http://www.modrails.com/documentation/Users%20guide%20Apache...

That might be true if you are going to use the tool precisely once and then never again, but this is your system's shell we're talking about. You're disrespecting your own time if you don't learn how it works.

> You said that rbenv isn't advanced shell scripting. You are right, it isn't - for us.

You're conflating the objective and subjective notions of complexity and difficulty respectively. rbenv is objectively simple and subjectively either easy or hard depending on your shell scripting experience. However, rvm is objectively complex and subjectively easy or hard depending on your Ruby environment customization needs. Programmers should prefer objective simplicity and leveraged familiarity every single time.

A small initial investment in learning your shell is significantly more valuable than a large delayed investment in learning RVM.

> Did you know that environment variables [...]

Absolutely everything you mention is discussed in great detail in the bash man pages. And even "in great detail" means that the ENVIRONMENT section fits on my 13" screen vertically at 80 columns and the INVOCATION section (which I found by searching for "bashrc") is no more than two screenfuls. That's a 10 minute trade for a lifetime of saving 5 minutes a piece on Stack Overflow visits.

I don't know. I don't use Ruby or RVM anymore.

> Which user thinks, "oooh, modifying dotfiles is so evil, I'll just type in this command every single time I open a terminal"?

I did. And it's not "every single time I open a terminal", it's "the once in a blue moon that I need to work on a legacy Rails app".

> They found in a user survey that 80% of the users want auto-switching

Obviously people who choose to use RVM are going to be people who like the way that RVM operates.

> If these problems are fixable then why throw the baby out with the bath water?

The bath water is the specific bugs I ran into. As you say, those may fixed and aren't the point. The baby is the general practice of automatically injecting things into dotfiles and messing with shell builtins. We should throw that away because when it fails, it leads to "spooky action at a distance" bugs that are hard to understand and that break totally unrelated things (the user is in a shell session where they aren't doing anything related to Ruby).

I do not understand why the[1] shell... which is a relatively small language... is so difficult for people to learn.

If you can find the time to learn Ruby, what stops you from learning a shell? What is the cost of ignoring it?

1. Preferably something resembling the proposed POSIX standard which might lend to portability. Bash is not necessarily the best choice unless every server you will ever use will be GNU userland/Linux kernel.