def sh (command, as: nil, quiet: false)
      as ||= @user
      output = ""
      synchronize do
        log.debug "sh #{command}", quiet: quiet
        result = nil
        ch = ssh(as).open_channel do |ch|
          ch.request_pty do |ch, success|
            "failed to acquire pty" unless success
            ch.exec(command) do |_, success|
              fail "failed to execute command" unless success
              ch.on_data do |_, data|
                log.trace "received #{data.bytesize} bytes stdout", quiet: quiet
                output << data
              end
              ch.on_extended_data do |_, _, data|
                log.trace "received #{data.bytesize} bytes stderr", quiet: quiet
                output << data.colorize(:red)
              end
              ch.on_request("exit-status") do |_, data|
                result = data.read_long
                log.trace "received exit-status #{result}", quiet: quiet
              end
            end
          end
        end
        ch.wait
        fail FailedCommand, output if result != 0
        output
      end
    end
def sh (command, as: nil, quiet: false)
      as ||= @user
      output = ""
      synchronize do
        log.debug "sh #{command}", quiet: quiet
        result = nil
        ch = ssh(as).open_channel do |ch|
          ch.request_pty do |ch, success|
            "failed to acquire pty" unless success
            ch.exec(command) do |_, success|
              fail "failed to execute command" unless success
              ch.on_data do |_, data|
                log.trace "received #{data.bytesize} bytes stdout", quiet: quiet
                output << data
              end
              ch.on_extended_data do |_, _, data|
                log.trace "received #{data.bytesize} bytes stderr", quiet: quiet
                output << data.colorize(:red)
              end
              ch.on_request("exit-status") do |_, data|
                result = data.read_long
                log.trace "received exit-status #{result}", quiet: quiet
              end
            end
          end
        end
        ch.wait
        fail FailedCommand, output if result != 0
        output
      end
    end
Execute a command on the host and return its output.
 @api private