Is there a Linux equivalent of CPU-z?

you can use CPU-G, see the example here

CPU-G is an application that shows useful information about your hardware. It collects and displays information about your CPU, RAM, Motherboard, some general information about your system and more

% dmidecode
% cat /proc/cpuinfo
% lspci -vvv

As root will all show you info about both CPU and memory, you might want to run update-pciids prior to some of those commands in download the newest version of the PCI ID list to ensure everything reports your hardware correctly.

Other answers about /proc/cpuinfo, lspci, dmidecode and other tools are helpful. I would try to get away with them first if I could.

But for big jobs, HAL is the major mechanism to enumerate and identify hardware on Linux. Strictly, speaking, HAL is an API accessible over the system DBus, but there are command-line tools to make HAL information available for human or script consumption.

To start out, try this:

$ lshal

The UDI is a namespace within HAL for all devices in your system. Everything else is key/value pairs where the keys are in a hierarchy defined in the HAL specification

I'm not familiar with CPU-z, but if you are interested in CPU information, search or grep for info.category = 'processor' which will give you a list of processors on the system, the manufacturer, whether they can throttle, etc. In general, info.category is the basic grouping of devices (battery, AC adapter, disk, etc.)

% cat /proc/cpuinfo
% dmidecode

x86info can decode CPU features and display them in human readable from.