Show interrupts

cat /proc/interrupts

show file(s) swap

cat /proc/swaps

Get the version of the kernal

cat /proc/version
OR
uname -r

Show version of the kernel

cat /proc/version

Show memory use

$ cat /proc/meminfo

Show network adpters and statistics

cat /proc/net/dev

Linux command to show information about the CPU

cat /proc/cpuinfo

# Result (example)
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 75
model name      : AMD Athlon(tm) 64 X2 Dual Core Processor 3600+
stepping        : 2
cpu MHz         : 2159.980
cache size      : 256 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
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 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy ts fid vid ttp tm stc
bogomips        : 4322.80
clflush size    : 64

processor       : 1
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 75
model name      : AMD Athlon(tm) 64 X2 Dual Core Processor 3600+
stepping        : 2
cpu MHz         : 2159.980
cache size      : 256 KB
physical id     : 0
siblings        : 2
core id         : 1
cpu cores       : 2
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 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy ts fid vid ttp tm stc
bogomips        : 4319.37
clflush size    : 64

Shows all mounted file systems in Linux

cat /proc/mounts