Getting System Information from Linux

Here are some commands that I commonly use to find information about my system. The amount of information you can get on your computer can be vast and varied - it depends on how detailed you want to go into each of the subsystem on your computer. I'll try to group them in order that is most sensible, and also, note that these commands may be Ubuntu/Debian specific.

Listing devices on your mainboard:

 
biosdecode                 # information about your BIOS
lshw                       # gets quite a bit of information on everything about your CPU
lspci                      # get devices on your PCI bus
lsusb                      # list devices on your USB
dmidecode                  # get device information via BIOS
fdisk -l                   # get partition info on your harddisk

Getting information on your OS:

cat /proc/cpuinfo          # get information about your processor 
cat /proc/meminfo          # shows memory usage
free                       # show available free memory
top                        # detailed memory usage by process
htop                       # a better version of top
lsof                       # shows which file handle is opened by processes
lsmod                      # shows loaded kernel modules
dmesg                      # output bootup information
lsb_release -a             # see which distro of OS you're using
ps -e aux                  # list all running processes
df --si                    # show amount of free disk space
hdparm -t harddisk_device  # show performance of harddisk
ifconfig                   # show network configuration
route                      # show network routing configuration
iwconfig                   # show wireless network information