Bash parameter expansion

Mon Aug 23 19:21:13 UTC 2010

On Mon, Aug 23, 2010 at 03:18:42PM -0400, Christopher Browne wrote:
> Ah, slick.

Yep.  So you can either go by the attachment point (by-path) and not care
which disk it is, just where is it attached, or use by-id and use the
serial number of the disk to identify it, or by label for filesystems
with labels (not whole disks), or by-uuid for filesystems with UUIDs
(again, not whole disks in most cases, although you can probably do PV's
for LVM that way).

udev is nifty.

> Here's sample output of this sort of thing:
> 
> ls  -l /dev/disk/by*
> /dev/disk/by-id:
> total 0
> lrwxrwxrwx 1 root root  9 Aug 19 11:19 ata-ST3320418AS_6VMF0G0D -> ../../sda
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part1
> -> ../../sda1
> lrwxrwxrwx 1 root root 11 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part10
> -> ../../sda10
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part2
> -> ../../sda2
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part3
> -> ../../sda3
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part4
> -> ../../sda4
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part5
> -> ../../sda5
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part6
> -> ../../sda6
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part7
> -> ../../sda7
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part8
> -> ../../sda8
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 ata-ST3320418AS_6VMF0G0D-part9
> -> ../../sda9
> lrwxrwxrwx 1 root root  9 Aug 19 11:19 scsi-SATA_ST3320418AS_6VMF0G0D
> -> ../../sda
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part1 -> ../../sda1
> lrwxrwxrwx 1 root root 11 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part10 -> ../../sda10
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part2 -> ../../sda2
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part3 -> ../../sda3
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part4 -> ../../sda4
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part5 -> ../../sda5
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part6 -> ../../sda6
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part7 -> ../../sda7
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part8 -> ../../sda8
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> scsi-SATA_ST3320418AS_6VMF0G0D-part9 -> ../../sda9
> lrwxrwxrwx 1 root root  9 Aug 19 11:19 wwn-0x5000c50027931ff1 -> ../../sda
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part1 ->
> ../../sda1
> lrwxrwxrwx 1 root root 11 Aug 10 11:32 wwn-0x5000c50027931ff1-part10
> -> ../../sda10
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part2 ->
> ../../sda2
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part3 ->
> ../../sda3
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part4 ->
> ../../sda4
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part5 ->
> ../../sda5
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part6 ->
> ../../sda6
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part7 ->
> ../../sda7
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part8 ->
> ../../sda8
> lrwxrwxrwx 1 root root 10 Aug 10 11:32 wwn-0x5000c50027931ff1-part9 ->
> ../../sda9
> 
> /dev/disk/by-path:
> total 0
> lrwxrwxrwx 1 root root  9 Aug 19 11:19 pci-0000:00:1f.2-scsi-0:0:0:0
> -> ../../sda
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part1 -> ../../sda1
> lrwxrwxrwx 1 root root 11 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part10 -> ../../sda10
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part2 -> ../../sda2
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part3 -> ../../sda3
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part4 -> ../../sda4
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part5 -> ../../sda5
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part6 -> ../../sda6
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part7 -> ../../sda7
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part8 -> ../../sda8
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> pci-0000:00:1f.2-scsi-0:0:0:0-part9 -> ../../sda9
> lrwxrwxrwx 1 root root  9 Aug 10 11:32 pci-0000:00:1f.2-scsi-1:0:0:0
> -> ../../sr0
> 
> /dev/disk/by-uuid:
> total 0
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> 64daee94-a903-4bbc-8d0a-86649e255bbc -> ../../sda5
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> 6c3211c2-9222-4a29-b56f-907c9ea55661 -> ../../sda6
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> 7480f326-b80b-4c22-ba3c-f5179d9d6d8b -> ../../sda9
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> 79c3ffa9-4b98-42b4-ab1a-a86582132ace -> ../../sda7
> lrwxrwxrwx 1 root root 11 Aug 10 11:32
> 935b1f6c-346b-4d8c-a074-a92306656935 -> ../../sda10
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> 9c6322f8-4ceb-42fb-b95f-9e34b834f4e8 -> ../../sda3
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> aea3961d-6f97-4cbe-ad27-b6e863cef67c -> ../../sda1
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> b38eb8c7-1f5f-4c9f-bfe8-963dcfe9a069 -> ../../sda8
> lrwxrwxrwx 1 root root 10 Aug 10 11:32
> c960ec6c-2bbc-4838-9099-1d986bbbbb77 -> ../../sda2

-- 
Len Sorensen
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