This article （https://skillhub.jp/courses/134/lessons/785） Based on, I ran the rails server on cloud9 and completed until I saw the screen of "Yay! You're on Rails!".
As a prior knowledge, I have taken the Rails learning course I of Progate.
However, there was a stumbling block even with such a simple procedure, so I will create this article as a memorandum.
--Cloud9 environment creation --Install Rails -** Creating a directory and moving an operation folder ** --Yarn, installation of webpacker --rails server start and stop
In conclusion, the installation of yarn and webpacker didn't work, and I got an error over and over again, and repeated things like "I'm not sure, so start over from creating the environment".
In addition to the error in this image, there were also command mistakes and typographical errors, which made me confused.
The operation directory was incorrect (= yarn and webpacker were installed incorrectly).
On the reference site, I did not think that it was important because I was rushing to create a directory → move the directory without any explanation, and somehow I was convinced that "If you install it, you should use the home directory !!" It seems that he was throwing an error because he was working with it.
Even if the installation location has changed, can I continue working even if I force it by passing a path like an environment variable in windows?
Anyway, it seems that it is better to think a little more about building the environment. It was not until I looked back that I realized that there was a lack of detail in my work because I was in a hurry to create a portfolio.