Ubuntu: Find CPU Information / Speed

How do I find out CPU Information such as speed, processor, and cache under Ubuntu Linux operating systems?

You need to use the following command to display all information about the CPU (open terminal and type the following command at bash prompt):
$ cat /proc/cpuinfo
Sample outputs:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model  : 15
model name : Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz
stepping : 11
cpu MHz  : 1596.000
cache size : 4096 KB
physical id : 0
siblings : 4
core id  : 0
cpu cores : 4
apicid  : 0
initial apicid : 0
fpu  : yes
fpu_exception : yes
cpuid level : 10
wp  : yes
flags  : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 

clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc 

arch_perfmon pebs bts rep_good pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 

xtpr pdcm lahf_lm tpr_shadow vnmi flexpriority
bogomips : 4800.18
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
....
..
processor : 3
vendor_id : GenuineIntel
cpu family : 6
model  : 15
model name : Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz
stepping : 11
cpu MHz  : 1596.000
cache size : 4096 KB
physical id : 0
siblings : 4
core id  : 3
cpu cores : 4
apicid  : 3
initial apicid : 3
fpu  : yes
fpu_exception : yes
cpuid level : 10
wp  : yes
flags  : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 

clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_

perfmon pebs bts rep_good pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr 

pdcm lahf_lm tpr_shadow vnmi flexpriority
bogomips : 4800.30
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:

To count processor (including cores), enter:
grep -c processor /proc/cpuinfo