Linux/unix System Analysis Command Quick check Manual

1.Hardware

CPU Information:cat/proc/cpuinfo

Physical Core number: statistical core

Number of logical CPUs: Statistical processor

Memory Information:

Free-m

One of the-+buffer is for Os/app.

Disk Information:

Fdisk-l

Df-h

IO Performance:

iostat-d-x-k 1 10

This command belongs to the Sysstat package

Observe await average IO operation wait time

Observe the percentage of%util in a second of IO operations-->100% represents a high load

To count the size of a directory:

Du-sh/root

Count all directory sizes in this directory:

Du-cks *

DD Command:

Making swap Files

Making a drive disk

Make ISO

such as: DD if=xx of =xx2 bs=65536 count=65536

View average load:

Top

Uptime

W

Past 1,5,15 mintues:the count number of process queue (ready)

If R is often greater than the number of logical CPUs and ID < 50, the CPU load is high.

Monitoring of overall system performance:

Vmstat 1 10

Process:r = number of processes waiting to be allowed b= non-disruptive sleep states

System:in = number of interrupts CS = CPU Switch

Cpu:us = CPU usage time;  SY = CPU system usage time; ID = Idle

R<5, b~=0 normal state;

u%+s% < 70% good performance.

2.System

OS Info:

Uname-a

File/sbin/init

Pci:

Lspci | grep "XXX"

Host Name query:

/etc/hosts

Native hostname:

/etc/sysconfig/network

Configure DNS Server

/etc/resolv.conf

Namserver $IP _addr

3.Network

Ifconfig-a

Ping

Netstat-an:

Established: Statistics of concurrency

Close-wait: Waiting for local request

Time-wait: Wait for enough time for the confirm to connect to the interrupt;

Statistics Command:

Netstat-an | awk '/^tcp/{++s[$NF]}end{for (A in S) print A, s[a]} '

Other:

Telnet $IP _addr $PORT

NC-NVV $IP _add $PORT

Route

Route = Netstat-r

Route-n

TRACEROUTE: Tracking Packets

Route add-net 192.168.20.0 netmask 255.255.255.0 GW 192.168.10.1

Route add-host $IP _addr Dev eth0

Boot up add:/etc/rc.local

Nslookup:ip address <--> domain name

>mail.163.com

server:10.1.1.1

address:10.1.1.2

or command--dig

Dig www.baidu.com +trace

Finger = W

Lsof-i:22

See which program 22 ports are occupied by

(LS opened file)

Sockstat:-c = connected; -L = Listening

PS Command:

Ps-axu

Vsz:virtual memory Size (KB)

RSS: Physical Memory (KB)

STAT:

D-death

R-ready

S-sleep

T-trace

Z-zombie

<-high priority

N-low Priority

Top command:

Pr:priority

Ni:priority number

Virt:virtual Memroy used

Res:physical Memory Used

Shr:share Memory Used

Stat:s-sleeping; r-running; Z-zombie; N-low Priority

Interactive commands:

P-cpu sort; M-memory sequencing; T-time sequencing; C-full command;

Kill & Killall Command;