[Error] Could not find generator 'devise:install' . rails g:devise install

発生したError

$ rails g:devise install

Running via Spring preloader in process 26089
Could not find generator 'devise:install'. 
Run `rails generate --help` for more options

解決した方法

開発中に何度も実行するようなrailsなどのコマンドを素早く実行することができるようになるrailsのプリローダであるspringを停止してからInstallするようにした。

１.springの起動を確認

$ bin/spring status

 8465 spring server | techpitgram | started 11 hours ago
 8467 ruby -I /home/ubuntu/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib -e require 'spring/application/boot'

２.springを停止

$ bin/spring stop

Spring stopped.

3.deviseをGemで再インストール

Gemfile

gem 'devise'

terminal

$ bundle install

Using devise 4.8.1

4. devise install

$ rails g devise:install 

     create  config/initializers/devise.rb
      create  config/locales/devise.en.yml
===============================================================================

Depending on your application's configuration some manual setup may be required:

  1. Ensure you have defined default url options in your environments files. Here
     is an example of default_url_options appropriate for a development environment
     in config/environments/development.rb:

       config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }

     In production, :host should be set to the actual host of your application.

     * Required for all applications. *

  2. Ensure you have defined root_url to *something* in your config/routes.rb.
     For example:

       root to: "home#index"
     
     * Not required for API-only Applications *

  3. Ensure you have flash messages in app/views/layouts/application.html.erb.
     For example:

       <p class="notice"><%= notice %></p>
       <p class="alert"><%= alert %></p>

     * Not required for API-only Applications *

  4. You can copy Devise views (for customization) to your app by running:

       rails g devise:views
       
     * Not required *

===============================================================================

参考にしたもの

まとめ

おそらく立ち上げた状態で操作したので上記のようなErrorが発生したのかな？？
railsコマンドがうまく動作しなかった時はspringを止めることも今後試したい。