Write Map to csv file failed - ruby using Open3

Question

Am trying to write map content to a csv file using Open3.This is the code am using

def run_command(command,exit_on_error=false,error_msg='')
    if command.nil? || command.empty?
      return nil
    end
    exit_status=0
    output=[]
    error=[]
    Open3.popen2e(command) do |stdin, stdout_and_stderr, wait_thr|
      pid = wait_thr.pid # pid of the started process.
      stdout_and_stderr.each do |line|  
        puts line 
        output=output+[line] 
      end
      
      exit_status = wait_thr.value
    end
    unless error.empty?
    end
    if exit_on_error && exit_status.exitstatus !=0
      exit exit_status.exitstatus
    end
    return {:returncode=>exit_status.exitstatus,:output=>output.map{|ln| ln.chomp}}
end

Map creation logic is given below

while (file = queue.deq)
  begin
    cat = 'cat'
    
    if file.split('.').last=='gz' || file.split('.').last=='zip'
      cat = 'zcat'
    end
            
    user_ids.each do |user|
      res = run_command("aws s3 cp #{file} - | #{cat} | grep #{user} | wc -l",true,'s3cmd stream failed')
      output = "#{user},#{file.split('/')[-1]},#{file.split('/')[-2]},#{res[:output][0]}"
              
      if "ab".eql?(file.split('/')[-2])
        data_source ="ab"         
      elsif  "cde".eql?(file.split('/')[-2])
        data_source ="cde"
      elsif "fgh".eql?(file.split('/')[-2])
        data_source ="fgh"
      elsif "jik".eql?(file.split('/')[-2])
        data_source ="jik"
      else
        data_source ="NA"
      end
    end
  end
end

Is it possible to write map object to a csv file? what was the mistake here. I don't have any basic for ruby. Expecting a quick replay

Note:I can able to write a string content to csv