Difference between revisions of "Sfdisk"
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| − | + | sfdisk is a command line utility to partition hard disks. Important because it can operate in a non-interactive way taking commands from STDIN. It can also produce output about the current state of the partitions on a device. With a little scripting it can be made to do the complex and confusing job of disk paritioning in preparation for installation of [[Peerix]]. | |
| − | ==Examples== | + | == Examples == |
| + | Here is an example of using sfdisk to examine the partitions on a physical disk. | ||
| + | <pre> | ||
| + | root@turing:~/peerix# sfdisk -l /dev/hda | ||
| + | |||
| + | Disk /dev/hda: 77545 cylinders, 16 heads, 63 sectors/track | ||
| + | Warning: extended partition does not start at a cylinder boundary. | ||
| + | DOS and Linux will interpret the contents differently. | ||
| + | Warning: The partition table looks like it was made | ||
| + | for C/H/S=*/255/63 (instead of 77545/16/63). | ||
| + | For this listing I'll assume that geometry. | ||
| + | Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 | ||
| + | |||
| + | Device Boot Start End #cyls #blocks Id System | ||
| + | /dev/hda1 * 0+ 4724 4725- 37953531 83 Linux | ||
| + | /dev/hda2 4725 4864 140 1124550 5 Extended | ||
| + | /dev/hda3 0 - 0 0 0 Empty | ||
| + | /dev/hda4 0 - 0 0 0 Empty | ||
| + | /dev/hda5 4725+ 4864 140- 1124518+ 82 Linux swap / Solaris | ||
| + | </pre> | ||
| + | |||
| + | Here we are writing a new partion onto the disk. NOTE: I have used the -n switch which means "don't really do this, just go through the motions". The ''';''' semicolon means "the whole thing", so we end up with one partition for the whole disk. This would be suitable for a Flash USB device where we want no unnecessary writes and we don't use a swap partition. | ||
| + | <pre> | ||
| + | root@turing:~/peerix# sfdisk -n /dev/hda << EOF | ||
| + | > ; | ||
| + | > EOF | ||
| + | |||
| + | Disk /dev/hda: 77545 cylinders, 16 heads, 63 sectors/track | ||
| + | Warning: extended partition does not start at a cylinder boundary. | ||
| + | DOS and Linux will interpret the contents differently. | ||
| + | Old situation: | ||
| + | Warning: The partition table looks like it was made | ||
| + | for C/H/S=*/255/63 (instead of 77545/16/63). | ||
| + | For this listing I'll assume that geometry. | ||
| + | Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 | ||
| + | |||
| + | Device Boot Start End #cyls #blocks Id System | ||
| + | /dev/hda1 * 0+ 4724 4725- 37953531 83 Linux | ||
| + | /dev/hda2 4725 4864 140 1124550 5 Extended | ||
| + | /dev/hda3 0 - 0 0 0 Empty | ||
| + | /dev/hda4 0 - 0 0 0 Empty | ||
| + | /dev/hda5 4725+ 4864 140- 1124518+ 82 Linux swap / Solaris | ||
| + | New situation: | ||
| + | Units = cylinders of 516096 bytes, blocks of 1024 bytes, counting from 0 | ||
| + | |||
| + | Device Boot Start End #cyls #blocks Id System | ||
| + | /dev/hda1 0+ 77544 77545- 39082679+ 83 Linux | ||
| + | /dev/hda2 0 - 0 0 0 Empty | ||
| + | /dev/hda3 0 - 0 0 0 Empty | ||
| + | /dev/hda4 0 - 0 0 0 Empty | ||
| + | Warning: no primary partition is marked bootable (active) | ||
| + | This does not matter for LILO, but the DOS MBR will not boot this disk. | ||
| + | </pre> | ||
| + | [[Category:Linux]] | ||
Latest revision as of 10:29, 3 September 2008
sfdisk is a command line utility to partition hard disks. Important because it can operate in a non-interactive way taking commands from STDIN. It can also produce output about the current state of the partitions on a device. With a little scripting it can be made to do the complex and confusing job of disk paritioning in preparation for installation of Peerix.
Examples
Here is an example of using sfdisk to examine the partitions on a physical disk.
root@turing:~/peerix# sfdisk -l /dev/hda Disk /dev/hda: 77545 cylinders, 16 heads, 63 sectors/track Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. Warning: The partition table looks like it was made for C/H/S=*/255/63 (instead of 77545/16/63). For this listing I'll assume that geometry. Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/hda1 * 0+ 4724 4725- 37953531 83 Linux /dev/hda2 4725 4864 140 1124550 5 Extended /dev/hda3 0 - 0 0 0 Empty /dev/hda4 0 - 0 0 0 Empty /dev/hda5 4725+ 4864 140- 1124518+ 82 Linux swap / Solaris
Here we are writing a new partion onto the disk. NOTE: I have used the -n switch which means "don't really do this, just go through the motions". The ; semicolon means "the whole thing", so we end up with one partition for the whole disk. This would be suitable for a Flash USB device where we want no unnecessary writes and we don't use a swap partition.
root@turing:~/peerix# sfdisk -n /dev/hda << EOF > ; > EOF Disk /dev/hda: 77545 cylinders, 16 heads, 63 sectors/track Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. Old situation: Warning: The partition table looks like it was made for C/H/S=*/255/63 (instead of 77545/16/63). For this listing I'll assume that geometry. Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/hda1 * 0+ 4724 4725- 37953531 83 Linux /dev/hda2 4725 4864 140 1124550 5 Extended /dev/hda3 0 - 0 0 0 Empty /dev/hda4 0 - 0 0 0 Empty /dev/hda5 4725+ 4864 140- 1124518+ 82 Linux swap / Solaris New situation: Units = cylinders of 516096 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/hda1 0+ 77544 77545- 39082679+ 83 Linux /dev/hda2 0 - 0 0 0 Empty /dev/hda3 0 - 0 0 0 Empty /dev/hda4 0 - 0 0 0 Empty Warning: no primary partition is marked bootable (active) This does not matter for LILO, but the DOS MBR will not boot this disk.
