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I just plugged in an external harddrive to a device running Ubuntu 12.04 LTS and when I attempt to umount the drive e.g. umount /dev/sdc1 or umount /media/harddrive the drive is still accessible via the menu that appears on the left. The only time it disappears from the menu or is no longer accessible when I right-click on the harddrive and select the option Safely remove.

Why does not umount not work?

Does safely remove umount and then poweroff?

How do I use the same command (safely remove) in the terminal?

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up vote 3 down vote accepted

umount only removes the mount; the device is still being seen by the system and is available for remounting. You can remove it safely.

eject will actually eject your device, removing it from the list of devices.

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Can you elaborate on what you mean by the device is still there? When using other distributions such as Debian, when I use the command umount the device is no longer visible however this doesn't appear to be the case with Ubuntu. Not sure whether that is the norm. So if I 'umount` a device, is it safe to remove it or do I then have to safely remove it? If so how do I achieve that via the command line? If not and I can simply safely remove the device, how can I do so with the command line? Does safely removing the device also flush all buffers and write them to the device? – PeanutsMonkey May 27 '12 at 6:13
Yes, you can unplug when a device is unmounted with umount, because the data should be all written when umount completes. Ubuntu just shows it is aware that you have the device plugged in. Umount and eject should be equivalent to safely remove. – johnshen64 May 27 '12 at 12:53
"Can you elaborate on what you mean by the device is still there?" I will edit the answer to do that. – Renan May 28 '12 at 13:18
it just means the kernel still list the device as accessible, so that you can mount it again. once you eject it, you would have to unplug and plug again to mount. i am not sure if this behavior is universal though, but is how my 12.04 install behaves, which is the same as some other distributions/versions that i have used. – johnshen64 May 29 '12 at 20:42

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