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

[Artif]

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:

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.

[theDaveTheRave]

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

[Artif]

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.

[varunendra]

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 -

~$ 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) -

~$ 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 -

$ ls -1 /dev/sd?? | cut -c 8-
a1
a2
a3
a4
a5
a6
a7
a8

Or,

$ 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.

[Artif]

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.

[steeldriver]

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

sudo lshw -C volume -short

[Artif]

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.

[oldfred]

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

[Artif]

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.