$lshw

List hardware

$lsblk

List block devices
[There are two types of devices; block and character. Block devices reads data in chunks while character devices reads in character ]

$lsusb

List usb devices

Combine to $less for better control

Eg: $lshw | less

When a new device is connected but not recognized:

1. Check if the device is listed in /dev/
2. Count the listing before and after the device is connected *$ls /dev/ | wc -l This gives word count that should be different when new device is detected

When a 4gb memory card was inserted

$dmesg

This generally tells what's happening.
(kernel ring buffer)

https://askubuntu.com/questions/285539/detect-and-mount-devices

Other ways to know about devices

dmesg
sudo fdisk OR sudo fdisk -l
sudo blkid
lsblk
mount
lsusb
usb-devices
df -h