code: public void list(String line, DispatchCallback callback) {
      int index = 0;
      DatabaseConnections databaseConnections = sqlLine.getDatabaseConnections();
      sqlLine.info(
          sqlLine.loc("active-connections", databaseConnections.size()));
  
      for (DatabaseConnection databaseConnection : databaseConnections) {
        boolean closed;
        try {
          closed = databaseConnection.connection.isClosed();
        } catch (Exception e) {
          closed = true;
        }
  
        sqlLine.output(
            sqlLine.getColorBuffer()
                .pad(" #" + index++ + "", 5)
                .pad(closed ? sqlLine.loc("closed") : sqlLine.loc("open"), 9)
                .pad(databaseConnection.getNickname(), 20)
                .append(" " + databaseConnection.getUrl()));
      }
  
      callback.setToSuccess();
    }
docs: Lists the current connections.
  
  @param line Command line
  @param callback Callback for command status