Return details about your processor:

# cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 6
model : 8
model name : AMD Athlon(tm) XP 2700+
stepping : 1
cpu MHz : 2164.892
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 mmx fxsr sse syscall mmxext 3dnowext 3dnow
bogomips : 4243.45

in doing this, I discovered that my AMD 2700 Athlon processor has a 256kb cache, while my 600mhz Athlon processor has 512kb!

Return just one line with the CPU model or clock speed:

# cat /proc/cpuinfo | grep model\ name
model name : AMD Athlon(tm) XP 2700+
# cat /proc/cpuinfo | grep MHz
cpu MHz : 2164.892

Get details about system memory:

# cat /proc/meminfo
MemTotal: 483684 kB
MemFree: 1924 kB
Buffers: 23512 kB
Cached: 379796 kB
SwapCached: 12 kB
Active: 61876 kB
Inactive: 369916 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 483684 kB
LowFree: 1924 kB
SwapTotal: 1052248 kB
SwapFree: 1051996 kB
Dirty: 6108 kB
Writeback: 0 kB
Mapped: 40692 kB
Slab: 39788 kB
Committed_AS: 112332 kB
PageTables: 1080 kB
VmallocTotal: 3645432 kB
VmallocUsed: 3548 kB
VmallocChunk: 3641332 kB
HugePages_Total: 0
HugePages_Free: 0
Hugepagesize: 4096 kB

Similarly, you can grep for certain fields. For example:

# cat /proc/meminfo | grep MemFree
MemFree: 1732 kB
# cat /proc/meminfo | grep MemTotal
MemTotal: 483684 kB