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I used Gparted to delete EFI (/dev/sda1) and Ubuntu (/dev/sda2) partitions on my secondary drive. The third partition (/dev/sda3) is for data, so I resized it in order to use all unallocated space I've got by deleting the first two partitions. Now, having only a unique partion on the disk, I would like to fix it's number, in order to get /dev/sda1. What's the easiest way to do it that works with a disk having GPT partition table? Thank you!

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    You do know that renumbering is just beautification for your own eyes, right? Anyway... you should have resized /dev/sda1 to be bigger than /dev/sda3. Then copy sda3 over sda1. File check sda1 and if no problems, remove sda3, resize sda1 accordingly. – user680858 May 26 '17 at 10:03
  • By the way... you said sda is your secondary drive ? Then what it the primary known as? – user680858 May 26 '17 at 10:07
  • What does primary drive has to do with it? My question is about /dev/sda drive. I said "secondary" because there is not Ubuntu installed anymore and so dev/sdb has become the primary one where I have Windows 10 installed. – Generoso May 26 '17 at 10:22
  • Nothing, I was just curious. It is usual for sda to be primary drive. – user680858 May 26 '17 at 10:24
  • You are right. I have to reverse the SATA connectors on my motherboard. :) Anyway, any suggestions to fix the number? The situation is that, I didn't mind to do as you explained! :D – Generoso May 26 '17 at 10:29
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You may use gdisk to rewrite the partition-table:

sudo gdisk /dev/sda
p  (the p-command prints the recent partition-table on-screen)
s  (the s-command sorts the partition-table entries)
p  (use the p-command again to see the result on your screen)
w  (write the changed partition-table to the disk)
q  (quit gdisk)

You will find most useful information about gdisk at http://www.rodsbooks.com/gdisk/

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  • Before I found your answer, I used fdisk to rewrite the patition-table: sudo fdisk /dev/sdb and then, in this order, x-f-r-w. It worked like a charm, getting /dev/sdb1 as I expected. I can deduce that using either fdisk or gdisk command is exactly the same and that fdisk command is proper for GPT patition-table too, is it? – Generoso May 27 '17 at 10:12
  • @Generoso Older versions of fdisk didn't support GPT, recent version does, probably fdisk uses gdisk in a way, difficult to find deeper insight... I wouldn't have tried it with fdisk, but good to know that it works too. +1 for your effort... – mook765 May 27 '17 at 10:26
  • Understood! :) Anyway, if I try to use gdisk, after I press s, it says: "You may need to edit /etc/fstab and/or your boot loader configuration". What about this message? – Generoso May 27 '17 at 20:20
  • @Generoso If you mount your partition via fstab you should check if the related fstab-entry is still valid. Your boot-loader configuration shouldn't be affected as the partition doesn't contain the OS but only data. – mook765 May 27 '17 at 20:25
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    Yes, it is just a warning, gdisk can't know what the purpose of the partition is, and gently gives this message. If you auto-mount your partition in your installed OS you should care about and check fstab-entry for validity after the changes. Imagine you auto-mount /dev/sda3 instead of using UUID, fstab-entry would fail because sda3 doesn't exist anymore. If you don't auto-mount the partition in any OS then you don't need to care. – mook765 May 28 '17 at 16:19
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You should have resized /dev/sda1 to be bigger than /dev/sda3. Then copy sda3 over sda1. File check sda1 and if no problems, remove sda3, resize sda1 accordingly.

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  • As /dev/sda1 was a (presumably FAT) ESP and /dev/sda3 already contained user data (perhaps FAT, but I'd guess not), doing exactly as you suggest might mean changing the filesystem type. That said, depending on the partitions' sizes, creating a new /dev/sda1 with the right filesystem type, copying the files over, deleting /dev/sda3, and then resizing /dev/sda1 might have been slightly safer than moving the start point of /dev/sda3. Of course, this is all moot now to the OP. – Rod Smith May 29 '17 at 1:30
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Intrigued by finding that last link and keen learning something new, I replayed Generoso's partition situation on my system using a 32GB USB drive. Below are my findings, but first my:

Conclusion: As my example is aimed at 1 (final) partition, near the end I merely changed its name. I did not touch the actual sectors. In the link in my comment above, an example is shown where sector number are moved around. I followed that and miserably goofed and destroyed the USB disk, proving how dangerous playing with partitions really is !!
Maybe my scenario also works with multiple partitions, feel free to try it yourself. I dare you to use your primary partition for it.. haha.
Ok, here are my:

Findings: Using Gparted I created 3 partitions, each 1 GB.

# fdisk -l /dev/sdc
Disk /dev/sdc: 30 GiB, 32176472064 bytes, 62844672 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xf33657fc

Device     Boot   Start     End Sectors Size Id Type
/dev/sdc1          2048 2099199 2097152   1G 83 Linux
/dev/sdc2       2099200 4196351 2097152   1G 83 Linux
/dev/sdc3       4196352 6293503 2097152   1G 83 Linux

Using Disks to mount partition 3.
Manually placed a file on it.

# ls -l /media/willem/cd4746ac-6d9f-4057-9396-a593ce2f301d/
total 21436
drwx------ 2 root root    16384 May 27 00:12 lost+found
-rw-r--r-- 1 root root 21930117 May 27 00:14 SomeFile.txt

Using Disks to unmount partition 3.
Using Gparted to remove partitions 1 & 2 and grow partition 3 to use the whole disk.

# fdisk -l /dev/sdc
Disk /dev/sdc: 30 GiB, 32176472064 bytes, 62844672 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xf33657fc

Device     Boot Start      End  Sectors Size Id Type
/dev/sdc3        8192 62844671 62836480  30G 83 Linux

Using Disks to mount partition 3.
Check the file on partition 3.

# ls -l /media/willem/cd4746ac-6d9f-4057-9396-a593ce2f301d/
total 21436
drwx------ 2 root root    16384 May 27 00:12 lost+found
-rw-r--r-- 1 root root 21930117 May 27 00:14 SomeFile.txt

Using Disks to unmount partition 3.
Copy the partition table from the drive.
Show the partition table.

# sfdisk -d /dev/sdc > sdc.tab
# cat sdc.tab
label: dos
label-id: 0xf33657fc
device: /dev/sdc
unit: sectors

/dev/sdc3 : start=        8192, size=    62836480, type=83

Using vi sdc.tab to change sdc3 into sdc1.
Apply the changed partition table.

# sfdisk --no-reread -f /dev/sdc < sdc.tab
Disk /dev/sdc: 30 GiB, 32176472064 bytes, 62844672 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xf33657fc

Old situation:

Device     Boot Start      End  Sectors Size Id Type
/dev/sdc3        8192 62844671 62836480  30G 83 Linux

>>> Script header accepted.
>>> Script header accepted.
>>> Script header accepted.
>>> Script header accepted.
>>> Created a new DOS disklabel with disk identifier 0xf33657fc.
Created a new partition 1 of type 'Linux' and of size 30 GiB.
/dev/sdc2: 
New situation:

Device     Boot Start      End  Sectors Size Id Type
/dev/sdc1        8192 62844671 62836480  30G 83 Linux

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

As soon as the command finishes, partition 1 auto-mounts.
Check the file.

# ls -l /media/willem/cd4746ac-6d9f-4057-9396-a593ce2f301d/
total 21436
drwx------ 2 root root    16384 May 27 00:12 lost+found
-rw-r--r-- 1 root root 21930117 May 27 00:14 SomeFile.txt

Using Disks to unmount partition 1.
Done.

PS. I did cat SomeFile.txt every time but I felt it unnecessary to include that output.

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  • Man, thank you for your detailed answer! Anyway, I solved my problem by using fdisk command. It's very very simple. Take a look to keep in mind if you will need it in future. – Generoso May 27 '17 at 10:06

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