Simple format is as follows:
%s/old-string/new-string/

Let us say you would like to find a word called "foo" and replace with "bar".

First hit [Esc] key

Type : (colon) followed by %s/foo/bar/ and hit [Enter] key.
:%s/foo/bar/
Above command will replace first occurrence of word foo with bar on all lines. The % is shorthand for all lines.

To replace all occurrences of word foo with bar on all lines, use the g option (which indicates all occurrences on a line).
:%s/foo/bar/g

Note that the g can be replaced with a number 1,2,...N to change only the n'th occurrence on each line.

You can also make changes on range of lines i.e. replace first occurrence of foo with bar on lines 5 through 20 only, enter:
:5,20s/foo/bar/

Following command will replace first occurrence of foo with bar starting at the current line for the next 100 lines:
:.,+100s/foo/bar/

Finally, you can match by words i.e. replace first occurrence of foo with bar starting at at the next line containing a word "test":
:/test/s/foo/bar/g
As usual you can specify ranges:
:/test/,/guest/s/foo/bar/g

Please note that all search/replace commands should be start with the [ESC]: keystroke combination only.

chgrp 用户组 文件或文件夹
chown 用户名 要改变的文件名
chmod u+x 文件名
chmod u-x 功能相反

config virtual pc IP and name

vi /etc/sysconfig/network

NETWORKING=yes

HOSTNAME=ydcvm0xx

GATEWAY=172.18.133.5 # fixed network gateway

vi /etc/hosts

172.0.0.1               localhost.localdomain localhost

172.18.133.xxx      ydcvm0xx

chgrp ngenplay ngenplay
chown ngenplay ngenplay

[ngensimu@ydcvml03 ~]$ ls -l /backup/
total 32
drwxrwxr-x 2 ngenplay ngenplay  4096 2010-12-13 17:12 as
drwx------ 2 root     root     16384 2008-11-17 10:36 lost+found
drwxr-xr-x 3 ngenplay ngenplay  4096 2011-01-11 14:50 ngenplay
drwxr-xr-x 3 ngensimu ngensimu  4096 2011-01-11 14:48 ngensimu