Hardware information from software:
dmidecode --- as root provides hardware and bios info from SMBIOS data structure. It doesn't directly access the hardware.
[Pkg: dmidecode]
lscpu --- cpu info, also obtainable from /proc/cpuinfo. [Pkg: util-linux]
lshw --- cpu, memory, disk, usb controllers, network adapters etc. Lshw extracts the information from different /proc files.
[Pkg: lshw]
lspci --- (e.g. -nnk) --- shows hardware and kernel modules. [Pkg: pciutils]
lsusb --- (e.g. -v) --- shows usb devices. [Pkg: usbutils]
inxi --- (e.g. -Fnx) a script that uses multiple sources to show hardware. [Pkg: inxi]
lsblk --- (e.g. --output NAME SIZE TYPE MOUNTPOINT UUID) ---shows block devices. [Pkg: util-linux]
hdparm --- (e.g. -i /dev/sda) --- hard disk info. [Pkg: hdparm]
smartctl --- (e.g. -i ) --- prints hard disk info including serial no. [Pkg: smartmontools]
hardinfo --- knows about PCI, ISA PnP, USB, IDE, SCSI, serial and parallel port devices. [Pkg: hardinfo]
cpu-x --- cpu, RAM, temperature, OS info. [Pkg: cpu-x]
hwinfo --- cdrom, zip, floppy, disks and partitions, network card, graphics card, monitor, camera, mouse, sound, pppoe, isdn,
modem, printer, scanner, bios, cpu, usb, memory and smp. [Pkg: hwinfo]
fdisk --- (e.g. -l) disks and partitions from root shell. [Pkg: fdisk]
ip --- (e.g. -a) networking device info. [Pkg: iproute2]
dmesg --- kernel messages on hardware. (For video card RAM e.g. | grep -i vram). [Pkg: util-linux]
lsmod --- lists modules. [Pkg: kmod]
modinfo --- info of named modules. [Pkg: kmod]
sensors --- temperatures of motherboard, cpu and video card. [Pkg: lm-sensors]
glxinfo --- OpenGL video info. (For video card RAM e.g. | grep -i video). [Pkg: mesa-utils]
xrandr --- screen capabilities and hardware video connections. [Pkg: x11-server-utils]
discover --- hardware detection utility