Web lists-archives.com

Re: Partition information as text file?




On Fri, Feb 01, 2019 at 09:00:06AM -0600, Richard Owlett wrote:
> On 02/01/2019 08:22 AM, Thomas Schmitt wrote:

[...]

> >So you need one or more scripts ... Then the script[s] would put out
> >the retrieved numbers in the text format which you desire.
> 
> The need for *ME* to write a script was a BASIC assumption to my
> asking about commands relevant to my task.

Perhaps the humble command "file" could be an ally in that. It's
not a complete solution, though...

Remember: "file" looks (with some exceptions, see below) into the
contents of a file and tries to find out what it is, by looking
for "magic numbers" (more precisely patterns) stored in a file
(/usr/share/misc/magic).

Here's a small session from my box (with some elisions marked as [...]

  tomas@trotzki:~$ mount
  /dev/sda1 on /boot type ext2 (rw,relatime,block_validity,barrier,user_xattr,acl)
  /dev/mapper/trotzki-root on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)
  /dev/mapper/trotzki-usr on /usr type ext4 (rw,relatime,data=ordered)
  /dev/mapper/trotzki-home on /home type ext4 (rw,relatime,data=ordered)
  /dev/mapper/trotzki-var on /var type ext4 (rw,relatime,data=ordered)
  [...]

(Note: my "partitions" are, with exception of /dev/sda1, which is the boot
partition, LVM volumes which are cut out from a physical volume which is
LUKS encrypted: I don't want someone to get at my (and my customer's)
data just because I leave the laptop in the metro).

Now:

  tomas@trotzki:~$ file /dev/mapper/trotzki-home 
  /dev/mapper/trotzki-home: symbolic link to ../dm-4

Ah.

  tomas@trotzki:~$ file /dev/dm-4
  /dev/dm-4: block special (254/4)

Not yet what we wanted. But:

  tomas@trotzki:~$ sudo file -s /dev/dm-4
  /dev/dm-4: Linux rev 1.0 ext4 filesystem data, UUID=c5d1ae98-df63-4c04-913d-661b82d38075 (needs journal recovery) (extents) (64bit) (large files) (huge files)

I guess that's not all info you want, but hey. Sudo is needed, because mere
mortals have no business in reading raw disks, usually; The "needs journal
recovery" sounds alarming, but remember that the thing is mounted, i.e.
active, so that's OK too.

Perhaps this can be a small building block for you.

I guess you'd like more info about the file system (size, what not).
Those commands (and their outputs!) are most probably file system
specific, as Thomas points out.

Cheers
-- t

Attachment: signature.asc
Description: Digital signature