2005/05/21 sfdisk

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© May 2005 Tony Lawrence

An alternative to fdisk, "sfdisk" is especially handy for scripting as it has direct support for reading actions from stdin. However, you need to read the man page very carefully if you are on intimate terms with fdisk, because sfdisk treats some command options quite differently.

Just as a inquiry tool, sfdisk has advantages over fdisk. For example, it can quickly list partitions or sizes:

# sfdisk -l /dev/hda

Disk /dev/hda: 4865 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/hda1   *      0+     23      24-    192748+  83  Linux
/dev/hda2         25    4731    4707   37808977+  83  Linux
/dev/hda3       4733    4861     129    1036192+  82  Linux swap
/dev/hda4          0       -       0          0    0  Empty
# sfdisk -s /dev/hda
39082680
 

You don't even need to tell it where the drives are, though my system does generate an error when it do that:,/p>

# sfdisk -l

Disk /dev/hdd: 2434 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/hdd1   *      0+     12      13-    104391   83  Linux
/dev/hdd2         13      45      33     265072+  82  Linux swap
/dev/hdd3         46    2433    2388   19181610   83  Linux
/dev/hdd4          0       -       0          0    0  Empty
Warning: start=63 - this looks like a partition rather than
the entire disk. Using fdisk on it is probably meaningless.
[Use the --force option if you really want this]
 

That makes me a little nervous.. For duplicating setups, it's "dump" mode can be used (probably after modification) as input for another sfdisk.

# sfdisk -d /dev/hda
# partition table of /dev/hda
unit: sectors

/dev/hda1 : start=       63, size=   385497, Id=83, bootable
/dev/hda2 : start=   401625, size= 75617955, Id=83
/dev/hda3 : start= 76035645, size=  2072385, Id=82
/dev/hda4 : start=        0, size=        0, Id= 0
 

Check the man page for more useful options.

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