Updating partition table dynamically

[tiziano-m]

Hello Everybody

I need to be able to refresh the paritition table (re-synch disks) without rebootting the machine.
After manually editing the MBR (master boot record) using dd or hexedit, I need a way to force the system to refresh the partitions table on the fly.

I figured that if I run fdisk and then and just use the 'w' (write) even if nothing was changed on fdisk, it will refresh the tables with the new settings on the MBR, but I need to implement this functionality in a script, therefore can't use that option.

[anomie]

See manpages for partprobe(8).

[tiziano-m]

Hi I tryed partprobe it takes a long time and after that if I execute 'cat /proc/partitions' I don't get the updated table.

fdisk still does it with no problems.


partprobe -h
Usage: partprobe [OPTION] [DEVICE]...
Inform the operating system about partition table changes.

-d, --dry-run do not actually inform the operating system
-s, --summary print a summary of contents
-h, --help display this help and exit
-v, --version output version information and exit

When no DEVICE is given, probe all partitions.

[i92guboj]

Hi I tryed partprobe it takes a long time and after that if I execute 'cat /proc/partitions' I don't get the updated table.

fdisk still does it with no problems.

You can always feed fdisk from a file, instead of stdin.

Create a file called "test.txt" containing this:

p
q

Now, do this on command line:

fdisk /dev/hda < test.txt

You get the idea... Modify it to suit your needs.

[tiziano-m]

Hey THANKS, that did it ! ! !

Now, just to be a pain and not have an extra file, is there a way to send that stdin directly form the line instead of creating another file?

Ends up being that the only command I have to send is 'w' that's all, not even a 'new line' or enter, after 'write' fdisk autommatically quits.

I tryed:
fdisk /dev/sda < 'w'
and others variants too, but it didn't work.

[i92guboj]

Sure, you want this:

fdisk /dev/sda << EOF
w
EOF

[rest of the script]

Everything until the EOF mark (end of file) is not interpreted by bash. Instead, it's used to feed fdisk. EOF closes the stream and returns the control to bash.

[tiziano-m]

Thanks a LOT !!!