Dmidecode in Linux

The dmidecode in Linux stands for Desktop Management Interface, abbreviated as DMI. The dmidecode is a Linux command that comes in handy in retrieving all details of your system’s hardware components, and it displays the output in a human-readable format. You can utilize the DMI on various Linux systems, including Debian, CentOS/RHEL, OpenSUSE, Fedora, and Arch Linux.

This guide dives into all details about using the dmidecode command in Linux, including the installation and examples of using the tool.

What is the purpose of dmidecode

Keeping a tab on the system’s hardware components is part of a Linux administrator job, and with a command like DMI, you can easily fetch the system’s details from the DMI table. It gets better since dmidecode will give the output in a human-readable format, and you can view all the details, such as BIOS, CPU details, serial numbers, etc.

Moreover, with DMI, you can get other crucial information, such as the supported memory or CPU by a given system. That way, you get to make informed decisions. The dmidecode mainly achieves a faster and cleaner way of analyzing the hardware components of a given system.

The best part about the dmidecode is that it lists the DMI table details in a record containing four main components. The components represent the syntax as retrieved in the DMI table.

The first is the handle. It is the unique identifier that allows referencing of records for identification. The second is the type, representing the various elements the particular computer can be composed of.

The third is the size which represents the length of each record. Lastly, the decoded values are the details of the particular record type.

For instance, the image below represents a dmidecode output sample.

In the above dmidecode command output, we can note the first component is the handle. For this case, the handle 0x0001. Next, we have the type of DMI as type 4. Further, we have the record size as 42 bytes; below it is the decoded values for our DMI type 4 which later we will note that type 4, according to the SMBIOS specification, represents the processor.

You can confirm so by noting the processor type. In this case, it’s highlighted as core i5.

Installing Dmidecode on Linux

Now that we understand what dmidecode means on Linux and how handy it comes, how about knowing how to install it on your system?

Debian / Ubuntu

You should find the dmidecode as a built-in tool for Ubuntu, especially for later versions. You can confirm so by checking its version using the below command.

dmidecode --version

If not installed, below is the command to install the dmidecode tool for Debian/Ubuntu.

sudo apt install dmidecode

You can note above that dmidecode is set to install in updated Ubuntu/Debian systems manually.

Fedora

To install the dmidecode on Fedora, use the command below.

sudo dnf install dmidecode

Arch Linux

For Arch, use the pacman command to install dmidecode with the below command.

sudo pacman -S dmidecode

That’s it. You now have dmidecode installed on your Linux system. Let’s move on to how to use and read the DMI table records.

DMI Table in Linux

So far, we’ve installed the dmidecode. The next thing is to use it to retrieve hardware component details. When using the dmidecode command, you must know the various DMI types and what they mean.

The dmidecode allows you to use the type name or the type ID of the information you want to retrieve about your hardware components. Check the below dmi table to know the DMI type number representing a given DMI type:

Type	Information
0	BIOS
1	System
2	Baseboard
3	Chassis
4	Processor
5	Memory Controller
6	Memory Module
7	Cache
8	Port Connector
9	System Slots
10	On Board Devices
11	OEM Strings
12	System Configuration Options
13	BIOS Language
14	Group Associations
15	System Event Log
16	Physical Memory Array
17	Memory Device
18	32-bit Memory Error
19	Memory Array Mapped Address
20	Memory Device Mapped Address
21	Built-In Pointing Device
22	Portable Battery
23	System Reset
24	Hardware Security
25	System Power Controls
26	Voltage Probe
27	Cooling Device
28	Temperature Probe
29	Electrical Current Probe
30	Out-of-band Remote Access
31	Boot Integrity Services
32	System Boot
33	64-bit Memory Error
34	Management Device
35	Management Device Component
36	Management Device Threshold Data
37	Memory Channel
38	IPMI Device
39	Power Supply
40	Additional Information
41	Onboard Devices Extended Information
42	Management Controller Host Interface

Instead of using the “type id” option for getting the hardware component data, we can use keywords that match specific keyword types. Besides, the keywords act as a shorthand for achieving the same. Take a look at the below table.

Keywords	Types
bios	0, 13
system	1, 12, 15, 23, 32
baseboard	2, 10, 41
chassis	3
processor	4
memory	5, 6, 16, 17
cache	7
connector	8
slot	9

Read on to find out how we use keywords using the -t option.

DMIdecode Examples

Using the DMI table displaying the DMI types, we can see the various options for using dmidecode. Take a look!

Get hardware information

Run the below command to display all the system’s hardware information without specifying the DMI type.

sudo dmidecode

You can scroll down the output checking the various output until you get to the last DMI type at the bottom.

Using DMI Type to Get Hardware Information

dmidecode command lets you filter the output using the DMI type keyword or ID.

For instance, to get the bios information, including the bios version and bios release date, you can use the keyword “bios.” Note that we are using the t option to stand for type. Refer to the man page for dmidecode for more options for the command.

sudo dmidecode --type bios

or

sudo dmidecode -t bios

To get the Cache information, you can use its keyword or the type id for the keyword, which is 7. Either of the below commands will work.

sudo dmidecode -t 7

or

sudo dmidecode -t cache

To get the hardware details for the system, use the below command.

sudo dmidecode -t system

For the details about the DIMMs and the physical memory device, you can use ID 17 to extract them.

sudo dmidecode -t 17

Below is our memory information retrieved from the DMI data.

The process is the same to get the hardware components of any DMI type. Refer to the table to use the associated keyword or its type ID, which also gives the same result.

The most important factor is knowing which information you want to retrieve and its corresponding keyword type or ID.

You can also combine the type option with other options to display different outputs. For instance, if you prefer dmidecode output in a hexadecimal format, use the --dump or -u option.

Let’s display the system components in a hexadecimal format using the below command.

sudo dmidecode --dump -t system

or

sudo dmidecode -u -t system

Using DMI String Keywords

The --string or -s options help display the DMI details using string keywords, which is helpful when you want to extract a given detail in the information extracted for a given DMI type. Common string keywords include bios release date, serial number, system information, bank locator, memory array mapped address, memory speed, etc.

Let’s have some examples of how to use it.

To get the system manufacturer name, we can use the string keyword “system-manufacturer,” as in the example below.

sudo dmidecode -s system-manufacturer

Another example is getting the chassis version. Use the following command.

sudo dmidecode -s chassis-type

Conclusion

For me, a few times it came as a handy command to check memory and serial number. Feel free to contribute, the source code is available on GitHub.

Let us know how it helped you to retrieve system information in the comment section.