Get the device name of connected USB disk

Question

I need to get the device names of all connected USB disks (ie sdd).

I have 3 USB disks plugged in, and 2 SATA disks:

$ find /sys/devices/ -name block        
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-7/3-7:1.0/host5/target5:0:0/5:0:0:0/block
/sys/devices/pci0000:00/0000:00:14.0/usb4/4-2/4-2:1.0/host6/target6:0:0/6:0:0:0/block
/sys/devices/pci0000:00/0000:00:14.0/usb4/4-5/4-5:1.0/host4/target4:0:0/4:0:0:0/block
/sys/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/block
/sys/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block

I want to ignore the SATA disks, but I need to list all the USB disks.

In the terminal, I can us ls and it will give me sdd:

$ ls /sys/devices/pci0000:00/0000:00:14.0/usb3/3-7/3-7:1.0/host5/target5:0:0/5:0:0:0/block
sdd

But I need to use this in a script. I need to iterate over all USB disks, and I don't know the exact path in advance, so I have to use wildcards (* or ?):

for DISK in $(ls /sys/devices/pci0000:00/0000:00:14.0/usb?/*/*:1.0/host?/target?:0:0/?:0:0:0/block) ; do
echo /dev/$DISK
done

the above only works if one USB disk is plugged in. If two or more disks are plugend in, I get sdd as well as the /sys path, which I don't want, ie:

/dev//sys/devices/pci0000:00/0000:00:14.0/usb3/3-7/3-7:1.0/host5/target5:0:0/5:0:0:0/block:
/dev/sdd
/dev//sys/devices/pci0000:00/0000:00:14.0/usb4/4-2/4-2:1.0/host6/target6:0:0/6:0:0:0/block:
/dev/sde
/dev//sys/devices/pci0000:00/0000:00:14.0/usb4/4-5/4-5:1.0/host4/target4:0:0/4:0:0:0/block:
/dev/sdc

how can I iterate only over sdd sde sdc ?

I am looking for a solution not using udev infrastructure, ie /dev/disk/by-path/

Answer 1

You can do it with lsblk command.

lsblk -l -o name,tran gives

NAME TRAN
sda  sata
sda1 
sdb  usb
sdc  usb
sr0  sata

-l stands for "list" format, so it's easier to parse. Otherwise, you would get a tree format like this:

NAME   TRAN
sda    sata
└─sda1
sdb    usb
sr0    sata

Specifying other flags will give you more information like FSTYPE, LABEL, UUID, MOUNTPOINT and many other, just run lsblk --help to see all options.

You may want to use --paths --noheadings --scsi flags to have output printed like this:

sata   /dev/sda
usb    /dev/sdb
usb    /dev/sdc
sata   /dev/sr0

and then grep over the input to filter out those lines with usb at the beginning of the line.

Answer 2

Do lsusb, it gives the name of the devices connected via the USB bus.

As in:

$ lsusb
Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 0421:0802 Nokia Mobile Phones CA-42 Phone Parent
Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

See also man lsusb

Description

lsusb is a utility for displaying information about USB buses in the system and the devices connected to them.