Rails5にrspecを導入しようと、bundle installした後に、下記コマンドを打ち込んだところターミナルが止まってしまった。

$ bundle exec rails generate rspec:install

ctrl + c で強制終了したところspring関連のところで止まっていたっぽい

    16: from bin/rails:3:in `<main>'
	15: from bin/rails:3:in `load'
	14: from /Users/ユーザ名/ワークディレクトリ名/アプリケーション名/rails/bin/spring:15:in `<top (required)>'
	13: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:70:in `require'
	12: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:70:in `require'
	11: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `<top (required)>'
	10: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `load'
	 9: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/bin/spring:49:in `<top (required)>'
	 8: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client.rb:30:in `run'
	 7: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/command.rb:7:in `call'
	 6: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/rails.rb:24:in `call'
	 5: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/command.rb:7:in `call'
	 4: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/run.rb:35:in `call'
	 3: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/run.rb:42:in `warm_run'
	 2: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/run.rb:62:in `run'
	 1: from /Users/ユーザ名//.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/client/run.rb:117:in `verify_server_version'

とりあえずspringを停止してみたところうまくいった。
springの停止コマンド

$ bin/spring stop 
Spring stopped.

再度rspecのコマンドを実行

$ bundle exec rails generate rspec:install
Running via Spring preloader in process 60241
      create  .rspec
      create  spec
      create  spec/spec_helper.rb
      create  spec/rails_helper.rb

無事ファイルが作られた。
springのstatusを確認したら自動的にspringも起動されていた。

$ bin/spring status                                                                                                               606ms  木  8/16 12:15:07 2018
Spring is running:

60196 spring server | rails | started 13 mins ago   
60230 spring app    | rails | started 13 mins ago | development mode