linux most common use

1. change password

 

passwd [user]

 

2. add user

useradd [user]

 

 bash:useradd:command not found

/usr/sbin/useradd 

or

#vi .bash_profile PATH=$PATH:/bin:/usr/sbin

 

3. view process of a port

lsof -i :8080

netstat -tlnp

 

4.

 

http://www.roboticfan.com/blog/user_2005/104/2009617176.shtml

 

http://xxxyrq369.blog.163.com/blog/static/35722482010316101140497/

 

5. monitoring

iostat

 

r/s

The number of read requests that were issued to the device per second.

w/s

The number of write requests that were issued to the device per second.

svctm

The average service time (in milliseconds) for I/O requests that were issued to the device.

vmstat

 

sar

If the %idle is near zero, your CPU is overloaded. If the %iowait is large, your disks are overloaded.

01:10:00 PM CPU %user %nice %system %iowait %idle01:20:00 PM all 7.78 0.00 3.34 20.94 67.9401:30:00 PM all 0.75 0.00 0.46 1.71 97.0801:40:00 PM all 0.65 0.00 0.48 1.63 97.2301:50:00 PM all 0.96 0.00 0.74 2.10 96.1902:00:00 PM all 0.58 0.00 0.54 1.87 97.0102:10:00 PM all 0.80 0.00 0.60 1.27 97.3302:20:01 PM all 0.52 0.00 0.37 1.17 97.9402:30:00 PM all 0.49 0.00 0.27 1.18 98.06Average: all 1.85 0.00 0.44 2.56 95.14