Results 1 to 9 of 9

Thread: How can I obtain a path to HDD's device file?

  1. #1
    Join Date
    Jan 2010
    Beans
    34

    Question How can I obtain a path to HDD's device file?

    There is a usual name for HHD's device file:
    /dev/vda

    The is a usual name for a partition:
    /dev/vdaX
    where X is a number.

    How can I obtain reliably all these names in a script or in any other way? What is a proper way to do it via Shell commands, via Perl code? Or, may be, there are other good and reliable ways? May be using another programming language?

    I may do:

    Code:
    sudo parted --list --machine /dev/sda
    It will display machine parseable output. Moreover, Parted supports GPT (Guided Partition Table, not MBR only), which is good for me. This is quite a good way for me. But I'm not shure, if there are another better and reliable ways.

  2. #2
    Join Date
    Feb 2007
    Location
    /home/paris
    Beans
    688
    Distro
    Lubuntu 12.10 Quantal Quetzal

    Re: How can I obtain a path to HDD's device file?

    Have a look at the comunity wiki docs for fstab. it should give you some usefull info, and things to search for.

    what are you hoping to acheive ?

    David
    Eee pc via Wubi install.
    evertying works straight out of the box

    My Launchpad page

  3. #3
    Join Date
    Jan 2010
    Beans
    34

    Re: How can I obtain a path to HDD's device file?

    Quote Originally Posted by theDaveTheRave View Post
    what are you hoping to acheive ?
    David
    Thank you for the link, it is useful.

    I'm working on automated Linux OS installer. I'm searching for a way to organise complex partitions layout wiping and creation, and flexible code structure/architecture.

    I need a graceful way to remove all data structures from a storage and, then, create my own layout. It seems to me, knowlege, about if a path exist, what is it, may be useful for me.

  4. #4
    Join Date
    Mar 2010
    Location
    India
    Beans
    7,207
    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: How can I obtain a path to HDD's device file?

    Quote Originally Posted by Artif View Post
    There is a usual name for HHD's device file:
    /dev/vda

    The is a usual name for a partition:
    /dev/vdaX
    where X is a number.

    How can I obtain reliably all these names in a script or in any other way?
    You can directly read the device files in the /dev directory, then trim the output as required. For example, the HDD device files in my /dev directory -
    Code:
    ~$ ls -1 /dev/sd??
    /dev/sda1
    /dev/sda2
    /dev/sda3
    /dev/sda4
    /dev/sda5
    /dev/sda6
    /dev/sda7
    /dev/sda8
    To get the device name (in case there are also sdb, sdc... etc. are present with valid partitions on them) -
    Code:
    ~$ ls -1 /dev/sd?? | cut -c 6-8 | sort -u
    sda
    You can also use "ls -1 /dev/sd? | cut -c 6-", but it will also list the devices which doesn't have a valid partition on it (e.g. - a modem's card reader with no card in it)

    To parse the partition numbers -
    Code:
    $ ls -1 /dev/sd?? | cut -c 8-
    a1
    a2
    a3
    a4
    a5
    a6
    a7
    a8
    Or,
    Code:
    $ ls -1 /dev/sd?? | cut -c 9
    1
    2
    3
    4
    5
    6
    7
    8
    ..if only the last number is required. But that may be confusing if more than one device is present.

    But anyway, I hope it gives you an idea to parse the parts of interest, then use them as they are or further strip them as you wish.
    Varun
    Help others by marking threads as [SOLVED], if they are. (See how)
    Wireless Script | Use Code Tags

  5. #5
    Join Date
    Jan 2010
    Beans
    34

    Re: How can I obtain a path to HDD's device file?

    In practice the names can be different. They may include subdirectories, they may include several letters and several separated numbers in a single "word". The letters and numbers depends on underlying storage's physical and logical structure. It can be complex.

    There is a part of kernel API:

    /proc/devices
    /proc/partitions

    Full path can not be obtained from the files.

    Also, there is the link https://help.ubuntu.com/community/Fstab

    It seems there are two ways:
    1) See sources. And do the job from scrutch.
    2) Parse output from a tools and files (sfdisk, blkid, /dev/disk/*).

    I'm wondering, are there any tools to enumerate all partitons on a device and have _reliable_ full path for each one? Reliable path - is a path, which is not generated using my own approximations. It must be obtained from a kernel API, from a reliable utility, as a ready for use item. It must not be constructed using my admissions.

  6. #6
    Join Date
    Apr 2012
    Beans
    5,060

    Re: How can I obtain a path to HDD's device file?

    I still don't really understand what you want or why, but there's also lshw e.g.

    Code:
    sudo lshw -C volume -short

  7. #7
    Join Date
    Jan 2010
    Beans
    34

    Re: How can I obtain a path to HDD's device file?

    Thank you for the help, it is useful.

    There is one more way: sudo blockdev --report

    This will give a list with full path for each block device mentioned in /proc/partitions file. The output can be parsed before and after partition creation. It is possible to use the difference between two outputs as a wanted full path to a partition. It is convenient to use a programming language with hash object support. It can be Perl, for example.

  8. #8
    Join Date
    Jun 2009
    Location
    Chicago Suburbs
    Beans
    Hidden!
    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: How can I obtain a path to HDD's device file?

    This also lists lots of info, but mine shows both ata (includes DVD), scsi (4 drives but not DVD) & wwn(only 2 of 4 drives?) as same drives?

    sudo ls /dev/disk/by-id
    For info on UEFI boot install & repair:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  9. #9
    Join Date
    Jan 2010
    Beans
    34

    Re: How can I obtain a path to HDD's device file?

    Some ways are more convenient, another ones less convenient, if one want them to be used by a program.

    It's simple task, as a human to have a look on single (or two) command's output and decide what is what. Lots of a tools may present acceptable output. It's much harder to gain a reliable tool, which can be used in a simple way by an "artificial intelligence".

    P.S. There is also lsblk utility.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •