XK0-004 · Question #267
A systems administrator is using a Linux laptop to troubleshoot network devices. The administrator runs the following command: # screen /dev/USB0 Which of the following does this command MOST likely…
The correct answer is D. It allows the administrator to interact with the character device connected to USB0. The screen command can open an interactive terminal session with a character device such as a USB-to-serial adapter, enabling direct console access to network equipment.
Question
A systems administrator is using a Linux laptop to troubleshoot network devices. The administrator runs the following command:
screen /dev/USB0 Which of the following does this command MOST likely accomplish?
Options
- AIt copies the network traffic from the device connected to USB0 and screens out rejected traffic.
- BIt logs all troubleshooting output from the monitor to external USB0 storage.
- CIt monitors USB0 waiting for a network device to be connected to it as an Ethernet device.
- DIt allows the administrator to interact with the character device connected to USB0.
How the community answered
(27 responses)- A7% (2)
- B4% (1)
- C11% (3)
- D78% (21)
Why each option
The `screen` command can open an interactive terminal session with a character device such as a USB-to-serial adapter, enabling direct console access to network equipment.
The `screen` command is a terminal emulator and session manager, not a packet capture or traffic filtering tool - it cannot copy or screen network traffic.
The `screen` command does not write output logs to external USB storage - it opens an interactive terminal session with the specified character device.
The `screen` command does not poll or wait for a device to be plugged in - it immediately opens a session with the device node already present at /dev/USB0.
The `screen` utility supports connecting directly to character devices like serial ports and USB-to-serial adapters (e.g., /dev/ttyUSB0). When a console cable connects a network device to the laptop via a USB adapter, running 'screen /dev/USB0 [baud_rate]' opens an interactive terminal session that lets the administrator send commands to and receive output from the device's console port. This is a standard technique for out-of-band management of routers and switches.
Concept tested: Using screen command with USB serial character devices
Source: https://linux.die.net/man/1/screen
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