Hardware

Command Description
dmesg Displays all the messages from Kernel ring buffer. With -k switch you can view kernel messages and with -u you can view userspace messages
cat /proc/cpuinfo Displays information about processes and CPUs of the system
cat /proc/meminfo Displays details on hardware memory
cat /proc/interrupts Lists the number of interrupts per CPU per I/O device
lshw Displays information on hardware configuration of the system. But this command must be run as super user or it will only report partial information
lsblk Displays block device related information of the machine. With -a you can view all block devices
free -m Shows used and free memory (-m for MB)
lspci -tv Shows information on PCI buses devices
lsusb -tv Shows information on USB devices
dmidecode Shows hardware info from the BIOS (vendor details)
hdparm -i /dev/sda Shows info about disk sda
badblocks -s /dev/sda Tests for unreadable blocks on disk sda
hdparm -tT /dev/sda Performs a read speed test on disk sda