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What is the command line equivalent of the Nautilus feature called "Safely Remove Drive". Specifically, I am removing a USB flash drive.

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The udisks command is most likely what you are looking for.

While sudo unmount /dev/sdXY will work, udisks can do this without root level (sudo) permissions.

If you have a drive /dev/sdXY, mounted, where X is a letter representing your usb disk and Y is the partition number (usually 1), you can use the following commands to safely remove the drive:

udisks --unmount /dev/sdXY
udisks --detach /dev/sdX

For a practical example, if I have the partition /dev/sdb1 mounted, I would run this to unmount and detach it:

udisks --unmount /dev/sdb1
udisks --detach /dev/sdb

If your drive is not mounted, or was never mounted, simply use the second command:

udisks --detach /dev/sdb

I originally found this through this question: https://superuser.com/a/430470/176493.

Using udisks2:

In the newer ubuntu distributions (I'm unsure of when the switch occurred), udisks2 is installed instead of udisks.

Mirroring the commands above, to unmount and detach a disk with udisks2:

udisksctl unmount -b /dev/sdXY
udisksctl power-off -b /dev/sdX

Example if my drive is /dev/sdb1:

udisksctl unmount -b /dev/sdb1
udisksctl power-off -b /dev/sdb

Similarly to above, power-off can be used to detach the drive even if there are no partitions mounted, or no partition was ever mounted:

udisksctl power-off -b /dev/sdb
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  • I get Detach failed: Not Authorized when I try to run it without root privileges. (Not a serious issue, but a small correction.) Oct 18 '15 at 9:59
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    Yes, I mounted with sudo, but I also umounted before trying to --detach. It's a trusty release of ubuntu server. Oct 18 '15 at 13:54
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    @morhook see updated answer with udisks2 support!
    – daboross
    Jul 13 '16 at 23:49
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    awesome! Thank you for this! I have been trying to move all of my activities to the terminal as much as possible, and this is one that I could not figure out how to do, since I write iso's to USB sticks all of the time, and need a way to eject them via the cli. Thanks again!
    – DPS
    Feb 16 '20 at 0:49
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    @AddisonKlinke In that case, using only the second command (--detach or power-off depending on your udisks version) should work.
    – daboross
    Oct 14 at 6:28
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The actual equivalent to Nautilus Mount/Unmount operation is gvfs-mount -m -d /dev/ice /some/directory and gvfs-mount -u /some/directory. This uses the same API that Nautilus uses, GIO virtual file system (gvfs), which provides different tools to use several services as mount points, such smb, NFS, FTP, block devices, etc.

To identify which device you need to unmount just use gvfs-mount -l which should be enough.

This solution has the peculiarity that it doesn't require for elevated permissions, since everything is managed by the umount/gvfsd/polkit services, which further resemblances the similarity with Nautilus behavior.

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    This seems to be the most correct answer. Although many of us are used to thinking of udisks (suggested in other answers) as "the way" non-root users mount and unmount removable disks on the desktop, as stated here gvfs-mount may use other mechanisms. (On my Ubuntu MATE Utopic system, the udisks package isn't even installed.) Oct 6 '14 at 1:52
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    Ubuntu 18.40 has gio which is the replacement for gvfs-mount.
    – studog
    Mar 6 '19 at 19:12
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Once you know the device, possibly using the df info as in @rcpao answer, the best way to "eject" the disk is, imho, using the same command that the graphical interface is using:

udisksctl unmount --block-device /dev/sdc1

I have a script to do a backup to a disk that I know will mount under /media/romano/movlin, and after the backup I do:

sync
udisksctl unmount -b $(mount | grep movlin   | cut -d" "  -f1)

Here, mount | grep movlin | cut -d" " -f1 will extract the device that is mounted under the label "movlin", (would be /dev/sdc1 in that case), and then it unmounts it.

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  • Is it really necessary to manually run sync before udisksctl unmount? Oct 6 '14 at 1:57
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    Probably not. But I am quite unsure of the correct behavior of the cache in general; I sometime feel that the USB drive is still flashing after the umount... during few seconds. Let it say it's a remnant of the old sync; sync; sync && poweroff...
    – Rmano
    Oct 6 '14 at 4:24
  • @Rmano I have seen the flashing on a supposedly dismounted flash drive (usually done through a gui under KDE) many times. I try to wait it out before unplugging it. This does look (to my untrained eye) like something is not quite right. It would be even worse with a flash drive with no activity indicator light.
    – Joe
    Oct 8 '14 at 20:32
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    Rmano, since udisks is no longer present by default in Ubuntu udisksctl may be a preferred solution. udisksctl power-off --block-device /dev/sdc turns off the light on an external USB Flash drive so it might be suitable as the next command to follow yours.
    – H2ONaCl
    Jan 3 '16 at 1:38
  • Other way to get the device findmnt -n -M /media/romano/movlin -o SOURCE => /dev/sdc1 Apr 10 at 20:14
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  1. df to find the mount point of your flash drive.

    rcpao@bun:~$ df
    Filesystem                   1K-blocks       Used  Available Use% Mounted on
    /dev/mapper/ubuntu--vg-root 1916153032  658404668 1160390336  37% /
    none                                 4          0          4   0% /sys/fs/cgroup
    udev                          16438692          4   16438688   1% /dev
    tmpfs                          3289976       2156    3287820   1% /run
    none                              5120          0       5120   0% /run/lock
    none                          16449860      18768   16431092   1% /run/shm
    none                            102400         48     102352   1% /run/user
    /dev/sda1                       240972      98990     129541  44% /boot
    /dev/sdc1                     60915712      20992   60894720   1% /media/rcpao/SD024-64GB
    
  2. Unmount using either /dev/sdc1 or /media/rcpao/SD024-64GB.

    rcpao@bun:~$ sudo umount /dev/sdc1
    [sudo] password for rcpao: 
    rcpao@bun:~$
    

    or

    rcpao@bun:~$ sudo umount /media/rcpao/SD024-64GB
    [sudo] password for rcpao: 
    rcpao@bun:~$
    
  3. You should be able to see the flash drive's eject icon disappear in nautilus as soon as umount finishes.

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    df looks very useful for identifying where the device is.
    – H2ONaCl
    Oct 5 '14 at 19:17
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    For a flash drive, this is reasonable. For a disk drive, "Safely Remove" also spins it down, which this solution does not do (see the answer by DaboRoss for that). Oct 6 '14 at 0:47
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    Yeah, udisks --detach is helpful for detaching drives completely after unmounting.
    – daboross
    Oct 6 '14 at 0:50
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    df and umount are standard UNIX utilities. It is always good to know them, because these will always work, while udisks is dependent on dbus and a running udisksd. Oct 6 '14 at 4:25
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    @NateEldredge: "For a flash drive, this is reasonable..." – actually, it's not and I'm down voting for this reason: last year I had to do an app qa deployment and naively used a quick command along the lines of cp /path/to /drive && umount drive. This rendered 2 flash drives (temporarily) unwritable until I realised it was the command that caused it. Running "Scan & repair" on a Windows machine fixed the drives. DaboRoss' answer below is much safer.
    – Andy E
    Oct 6 '14 at 12:32
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eject from the eject package:

sudo eject /dev/sdX

appears to umount all partitions, and put the device in a state that you must remove and reattach it to remount.

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  • For a few application this eject command is the best way to do it. Most of the other answers are "good enough" but technically the Eject Icon on Nautalis does not do things like power-off the device. In my experience eject is closer to the functionality of the eject usb button itself. If you want to avoid sudo you can add yourself to the disk group (requires log-out and log in). The command for this is "sudo adduser user disk"
    – SpiRail
    Feb 14 '18 at 10:56

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