CompTIA Linux+ (XK0-004) — Question 160

A Linux administrator needs to remove a USB drive from a system. The unmount command fails, stating the device is busy. Which of the following commands will show the reason for this error?

Answer options

• A. lsusb | grep /mnt/usb
• B. mount | grep /mnt/usb
• C. ps aux | grep /mnt/usb
• D. lsof | grep /mnt/usb

Correct answer: D

Explanation

The correct command is 'lsof | grep /mnt/usb' as it lists open files and their associated processes, helping to identify what is keeping the USB device busy. The other commands do not provide information about processes using the device; 'lsusb' shows connected USB devices, 'mount' lists mounted filesystems, and 'ps aux' displays running processes without focusing on file usage.