USB Drive – How to Eject USB Drives Using Eject Command

Well, there is no ready-for-that software I know. But you can write your own script, which will be started when pendrive is inserted|removed from usb port. This script would be run by udev if you add this to /etc/udev/rules/99-local.rules:

ACTION=="add|remove", SUBSYSTEM=="block", KERNEL=="sd*", RUN+="/usr/local/bin/usb-add.sh"

and then in this script you will have following environment variables:

ACTION=add (or remove)
DEVLINKS='/dev/disk/by-id/usb-TDK_LoR_TF10_0703293903BE2444-0:0 /dev/disk/by-path/pci-0000:00:16.2-usb-0:1.1:1.0-scsi-0:0:0:0'
DEVNAME=/dev/sdf
DEVPATH=/devices/pci0000:00/0000:00:16.2/usb7/7-1/7-1.1/7-1.1:1.0/host14/target14:0:0/14:0:0:0/block/sdf
DEVTYPE=disk ← this is important to check in script
ID_BUS=usb ← this is important to check in script
ID_FS_TYPE=
ID_INSTANCE=0:0
ID_MODEL=TF10 ← model
ID_MODEL_ENC='TF10\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20'
ID_MODEL_ID=070a
ID_PART_TABLE_TYPE=dos
ID_PART_TABLE_UUID=686bc5da
ID_PATH=pci-0000:00:16.2-usb-0:1.1:1.0-scsi-0:0:0:0
ID_PATH_TAG=pci-0000_00_16_2-usb-0_1_1_1_0-scsi-0_0_0_0
ID_REVISION=PMAP
ID_SERIAL=TDK_LoR_TF10_0703293903BE2444-0:0
ID_SERIAL_SHORT=0703293903BE2444 ← serial number
ID_TYPE=disk
ID_USB_DRIVER=usb-storage
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=TDK_LoR ← vendor
ID_VENDOR_ENC='TDK\x20LoR\x20'
ID_VENDOR_ID=0718

You can examine the pendrive with:

fdisk -l ${DEVNAME}

to get capacity and partition layout. And do various stuff like that. You can store information in file or in database. All is up to you. You can even deny access to this device if you like by sending SCSI STOP UNIT and removing the drive from system.

It is also important to check the ${ID_BUS} to examine only usb devices. It is important to check the ${DEVTYPE} because the script will also be called for every partition on usb device:

DEVLINKS='/dev/disk/by-id/usb-TDK_LoR_TF10_0703293903BE2444-0:0-part1 /dev/disk/by-label/BACKUPS /dev/disk/by-path/pci-0000:00:16.2-usb-0:1.1:1.0-scsi-0:0:0:0-part1 /dev/disk/by-uuid/0FAA-E0EB'
DEVNAME=/dev/sdf1
DEVPATH=/devices/pci0000:00/0000:00:16.2/usb7/7-1/7-1.1/7-1.1:1.0/host18/target18:0:0/18:0:0:0/block/sdf/sdf1
DEVTYPE=partition
ID_BUS=usb
ID_FS_LABEL=BACKUPS ← filesystem label
ID_FS_LABEL_ENC=BACKUPS
ID_FS_TYPE=vfat
ID_FS_USAGE=filesystem
ID_FS_UUID=0FAA-E0EB
ID_FS_UUID_ENC=0FAA-E0EB
ID_FS_VERSION=FAT32
ID_INSTANCE=0:0
ID_MODEL=TF10
ID_MODEL_ENC='TF10\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20'
ID_MODEL_ID=070a
ID_PART_ENTRY_DISK=8:80
ID_PART_ENTRY_NUMBER=1
ID_PART_ENTRY_OFFSET=2048
ID_PART_ENTRY_SCHEME=dos
ID_PART_ENTRY_SIZE=15104000 ← size ;)
ID_PART_ENTRY_TYPE=0xc
ID_PART_ENTRY_UUID=686bc5da-01
ID_PART_TABLE_TYPE=dos
ID_PART_TABLE_UUID=686bc5da
ID_PATH=pci-0000:00:16.2-usb-0:1.1:1.0-scsi-0:0:0:0
ID_PATH_TAG=pci-0000_00_16_2-usb-0_1_1_1_0-scsi-0_0_0_0
ID_REVISION=PMAP
ID_SERIAL=TDK_LoR_TF10_0703293903BE2444-0:0
ID_SERIAL_SHORT=0703293903BE2444
ID_TYPE=disk
ID_USB_DRIVER=usb-storage
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=TDK_LoR
ID_VENDOR_ENC='TDK\x20LoR\x20'
ID_VENDOR_ID=0718

Maybe it is a good idea to limit access when ${DEVTYPE}=disk but store information about all partitions – ${DEVTYPE}=partition.

HTH, Cheers

Use udisksctl to power off the drive:

   power-off
       Arranges for the drive to be safely removed and powered off. On the OS side this includes ensuring that
       no process is using the drive, then requesting that in-flight buffers and caches are committed to stable
       storage. The exact steps for powering off the drive depends on the drive itself and the interconnect
       used. For drives connected through USB, the effect is that the USB device will be deconfigured followed
       by disabling the upstream hub port it is connected to.

so e.g.

udisksctl power-off --block-device /dev/sdb

You can run the command as a regular user, no need for root access.
If you prefer a gui, gnome disks has a button to "power off this disk".