Many new Linux users have trouble determining the true specs of their Linux machine from command line. Linux GUI software's have evolved over past few years and provide the same details in very beautiful laid out manner; however an administrator/home-user may not have luxury of those tools on every machine.

So in this quick guide we will learn how to find specs of your Linux machine from command line. By the end of this guide you will be able to obtain full inventory of all components on your Linux machine within minutes. This should also help you in finding correct drivers and support for your hardware's chipset.

Part 1: Finding Hardware Details with lspci

lspci is a utility for displaying information about all PCI buses in the system and all devices connected to them. By default, it shows a brief list of devices. However you can use the various lspci options to request either a more verbose output or output intended for parsing by other programs.

[root@localhost ~]# lspci
00:00.0 Host bridge: Intel Corporation 82865G/PE/P DRAM Controller/Host-Hub Interface (rev 02)
00:02.0 VGA compatible controller: Intel Corporation 82865G Integrated Graphics Controller (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #1 (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev c2)
00:1f.1 IDE interface: Intel Corporation 82801EB/ER (ICH5/ICH5R) IDE Controller (rev 02)
03:08.0 Ethernet controller: Intel Corporation 82562EZ 10/100 Ethernet Controller (rev 02)
....

So now I know that my Graphics chip is “Intel Corporation 82865G Integrated Graphics Controller" and would take me a minute to search for drivers for that by searching the fine web. Here is the description of the line :

You may also use -v or -vv flags to display more information. When I used lspci -v, I get more details for my Graphic Chip

00:02.0 VGA compatible controller: Intel Corporation 82865G Integrated Graphics Controller (rev 02) (prog-if 00 [VGA])
Subsystem: IBM Unknown device 0285
Flags: bus master, fast devsel, latency 0, IRQ 185
Memory at f0000000 (32-bit, prefetchable) [size=128M]
Memory at e8000000 (32-bit, non-prefetchable) [size=512K]
I/O ports at 1800 [size=8]
Capabilities: [d0] Power Management version 1


Lspci utility reads some information from the PCI bus, and then collects additional information from its own database of hardware id's. This additional information is stored at /usr/share/misc/pci.ids and it contains information such as hardware-id, vendor, devices, classes and subclasses. Let's find our device in this file:

[root@localhost ~]# cat /usr/share/hwdata/pci.ids | grep "82865G Integrated Graphics Controller"
82865G Integrated Graphics Controller


As you can see our device is also listed in the hardware list. This hardware list is maintained at http://pciids.sourceforge.net, and you can use the update-pciids utility to download the most recent version.

Part 2: Finding Hardware Details with dmesg

dmesg is Linux command that is used to examine or control the kernel ring buffer. The program helps users to print out their boot-up messages.

Lspci worked well to discover our PCI devices but we want inventory of all devices on the system. Using dmesg we can view hardware details of everything detected by our operating system.

[root@localhost ~]# dmesg | less
Normal zone: 59248 pages, LIFO batch:15
DMI present.
Allocating PCI resources starting at 20000000 (gap: 10000000:eec00000)
Detected 2793.055 MHz processor.
Built 1 zonelists. Total pages: 63344
Kernel command line: ro root=/dev/VolGroup00/LogVol00 rhgb quiet
Enabling fast FPU save and restore... done.
Initializing CPU#0
CPU 0 irqstacks, hard=c07ae000 soft=c078e000
Memory: 244136k/253376k available (2139k kernel code, 8732k reserved, 866k data, 240k init, 0k highmem)
.....

As you can see dmesg gives you a lot of details, so we will use grep to restrict information to what we want. Let's say, we are interested in memory installed in the system.

[root@localhost ~]# dmesg | grep -i memory
Memory: 244136k/253376k available (2139k kernel code, 8732k reserved, 866k data, 240k init, 0k highmem)
Freeing initrd memory: 2124k freed
Total HugeTLB memory allocated, 0
Non-volatile memory driver v1.2
agpgart: Detected 8060K stolen memory.
Freeing unused kernel memory: 240k freed
.....

Similarly you can grep for whatever hardware you are trying to troubleshoot, for example CPU, USB etc.

Part 3: Finding Hardware Details from /proc

Sometimes you will want to monitor physical memory and CPU information on a running system in real time. For doing this, you will have to read the /proc file system. You might be thinking about `top` utility, but that utility also reads information from /proc file system. Make sure you only use `cat` command to view the information and do not change any of the files in /proc.

Doing an `ls` on /proc folder you will see various files and folders which contain information about your system.

Now let's start looking at what these files contain, starting with cpuinfo.

[root@localhost ~]# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Pentium(R) 4 CPU 2.80GHz
stepping : 9
cpu MHz : 2793.055
cache size : 512 KB
..


Now let's dig deeper and go inside a folder, I am going inside the `ide` folder and reading details for my hard disk.

[root@localhost ~]# cat /proc/ide/ide0/hda/driver
ide-disk version 1.18
[root@localhost ~]# cat /proc/ide/ide0/hda/capacity
78156288
[root@localhost ~]# cat /proc/ide/ide0/hda/model
IC35L060AVV207-0


Part 4: Getting More Information about your HDD using fdisk

In our last step using /proc, we obtained very basic information about our Hard Disk Settings. Now lets dig deeper by using `fdisk` command available in Linux. We will now try to obtain information about partitions, space available, space allocated, swap and more.

`fdisk` is the partition table manipulator tool for Linux. Generally hard disks are divided into one of more logical disks, also known as partitions. This partition information is stored in partition table found on sector 0 of the disk.

To display all partitions on your system, just type:

[root@localhost ~]# fdisk -l
Disk /dev/hda: 40.0 GB, 40016019456 bytes
255 heads, 63 sectors/track, 4865 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/hda1 * 1 13 104391 83 Linux
/dev/hda2 14 4865 38973690 8e Linux LVM


And to view details of a particular drive, let say you have hda and hdb drives then type fdisk -l /dev/hda

Part 5 (UPDATE) : Reading BIOS information using dmidecode command

dmidecode tool dumps your system's DMI (Desktop Management Interface) table contents in a human-readable format. This table contains information regarding system's hardware components, as well as BIOS revisions etc. dmidecode output not only describes system current configuration, but also reports the BIOS limitations on supported CPU speed, Maximum Memory allowed and more.

Now lets say I want to restrict information to certain areas of DMI, I can do that by using the option -t and specifying what type of information I am interested in. For example, Processor Information is DMI type 4 and Memory Device is DMI type 17.

I hope this tutorial helps you as much as it helped my friend who was installing MythTV on Fedora and kept on opening his box for hardware details :)