anchor.diff:  If a server is already running, the command only displays the server's PID. A new server will not be started.
   
   ```console
  -% rubocop --start-server
  +$ rubocop --start-server
   RuboCop server (16060) is already running.
   ```
   
   The server process name is basically `rubocop --server` and the project directory path:
   
   ```console
  -% ps aux | grep 'rubocop --server'
  +$ ps aux | grep 'rubocop --server'
   user             16060   0.0  0.0  5078568   2264   ??  S     7:54AM   0:00.00 rubocop --server /Users/user/src/github.com/rubocop/rubocop
   user             16337   0.0  0.0  5331560   2396   ??  S    23:51PM   0:00.00 rubocop --server /Users/user/src/github.com/rubocop/rubocop-rails
   ```
  
positive.code: 
  There are two ways to enable server:
  
  - `rubocop --server` ... If server process has not started yet,
  start server process and execute inspection with server.
  - `rubocop --start-server` ... Just start server process.
  
  When the server is started, it outputs the host and port.
  
  ```console
  % rubocop --start-server
  RuboCop server starting on 127.0.0.1:55772.
  ```
  
  
negative.code: 
  These are the command-line options for server operations:
  
  |===
  | Command flag | Description
  
  | `--server`
  | If a server process has not been started yet, start the server process and execute inspection with server.
  
  | `--no-server`
  | If a server process has been started, stop the server process and execute inspection without the server.
  
  | `--restart-server`
  | Restart server process.
  
  | `--start-server`
  | Start server process.
  
  | `--stop-server`
  | Stop server process.
  
  | `--server-status`
  | Show server status.
  |===
  
  TIP: You can specify the server host and port with the `$RUBOCOP_SERVER_HOST`and the `$RUBOCOP_SERVER_PORT` environment variables.
  
  == Environment Variables
  
  