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I have searched google, I've searched this website, I've searched using various terms, phrases, using quotes and without quotes and I cannot find the answer to this seemingly easy thing to do.

How do you mount a hard disk from the command line as read-only? I don't want or need a link to the man page, I want the exact thing I will have to type in if the following is true:

  • disk to mount is on /dev/sda
  • it is 2 TB -it is critical that I mount it read-only and not read-write. Very critical.
  • I'm doing it from a live ubuntu cd so I have no business to edit the fstab or any file for that matter
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up vote 44 down vote accepted

You do not mount /dev/sda, that refers to the entire disk. You mount /dev/sda1 or whatever partition you want.

Make a mount point, call it anything you like.

sudo mkdir /media/2tb


sudo mount -o ro /dev/sda1 /media/2tb

See man mount or

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I am plugging a USB connected drive into Ubuntu 12.04 and the system is mounting it automatically. In Terminal, if I just say "mount" it shows me the current info. I want to remount it read-only.

Extrapolated from man mount(8):

sudo mount -o remount,ro /dev/sdb4 /media/HP_TOOLS

Seemed to work nicely. Had to do it for each automounted partition.

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