UUID confusion revisited

NoOp glgxg at sbcglobal.net
Tue Mar 25 00:09:26 UTC 2008


On 03/24/2008 04:34 PM, SYNass IT Ubuntu / Linux wrote:
> On Mon, 2008-03-24 at 14:25 -0700, NoOp wrote:
>> On 03/21/2008 06:53 AM, JosephK wrote:
>> > Following the recent posts regarding UUIDs I thought I'd take a look at
>> > mine as I'm forever installing and deleting different Linux distros. I
>> > have 3 drives with Gutsy on sda as my main distro for the moment.
>> > However, if I instal another distro on sdb or sdc and after a few months
>> > use I decide I like it then it may be that my main distro is on sdc and
>> > at a later date sda could house something else.
>> > 
>> > The upshot of this is that when I checked my /etc/fstab against
>> > /dev/disk/by-uuid I found that none of the 3 swap partitions (one on
>> > each drive) were labelled correctly so I was using no swap space.
>> > 
>> > I've knocked together a quick script to compare the UUIDs in
>> > /dev/disk/by-uuid with the mounted disks in /etc/fstab. If it of any use
>> > to you please feel free to use, modify or what you will. Any
>> > constructive criticism is welcomed as I am just starting to learn bash
>> > shell scripting.
>> > 
>> > #!/bin/sh
>> > 
>> > ls -l /dev/disk/by-uuid/ |\
>> > awk '{print $10, "UUID="$8}' | sort |\
>> > awk -F"/" '{print $3}' > drives.tmp
>> > 
>> > cat /etc/fstab |\
>> > sed -e '/.*\/dev.*$/N;s/\n */ /' |\
>> > sed -e 's;^# *;;' |\
>> > sed -e 's/\(^\/dev\/[a-z0-9]* UUID=[a-z0-9]\{8\}-[a-z0-9]\{4\}-[a-z0-9]\{4\}-[a-z0-9]\{4\}-[a-z0-9]\{12\}\).*/\1/' |\
>> > sed -e '/^\/dev\/.*UUID.*/!d' |\
>> > sed -e 's/^\/dev\///' > mounts.tmp
>> > 
>> > join -a 1 drives.tmp mounts.tmp
>> > 
>> > 
>> 
>> Cool! I just saved as uuidcompare and:
>> 
>> sh uuidcomare
>> 
>> Works great, thanks.
>> 
>> Thanks
> 
> Hi Joseph and NoOp
> Your topic and script interests me too !
> 
> The topic:
> As a newbie I am preparing my Ubuntu 8.04 LTS to be better than my first
> installation.
> Thinking of 2 Ubuntu's (one PROD & the other TEST) with sharing the
> common data i.e. /BOOT, /HOME and SWAP !?
> 
> Your recommendations / suggestions and warnings are very appreciated !
> 
> The script:
> As newbie I am struggling with these helpful commands and scripts and 
> would like to understand better how to save a script like yours !
> 
> I have already saved it as UUIDcomp on desktop and checked for /bin/sh
> location 
> assuming that sh is a folder under bin !? I seem to be wrong !!
> 
> Can you help me little better ? ;-)
> 
> TIA and cheers, svobi
> 
> 

Open the text editor (gedit)
  Copy & paste the script into the new file
   Save as uuidcompare (or whatever you want to name it) into one of
your home folders. Exit the text editor.

Open a terminal
   cd to the folder where you saved it
     issue the shell command:
      sh <uuidcompare/name>

sh is the shell command, info (in terminal window) is:

man sh






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