首先下载Flash Player 9的安装包install_flash_player_9_linuxtar.gz，然后解压，在终端以root身份执行flashplayer-installer
之后会出现如下提示
Copyright(C) 2002-2006 Adobe Macromedia Software LLC. All rights reserved.
Adobe Flash Player 9 for Linux
Adobe Flash Player 9 will be installed on this machine.
You are running the Adobe Flash Player installer as the “root” user.
Adobe Flash Player 9 will be installed system-wide.
Support is available at http://www.adobe.com/support/flashplayer/
To install Adobe Flash Player 9 now, press ENTER.
To cancel the installation at any time, press Control-C.
按下回车继续安装…
NOTE: Please exit any browsers you may have running.
Press ENTER to continue…
又提示你说，要关闭所有现在运行的浏览器，并按下回车继续
Please enter the installation path of the Mozilla, SeaMonkey,
or Firefox browser (i.e., /usr/lib/mozilla):
在这里，安装程序会询问你的浏览器安装目录地址，输入就可以了，我用的是Ubuntu，默认的Firefox安装在/usr/lib/firefox
------- Install Action Summary -------
Adobe Flash Player 9 will be installed in the following directory:
Browser installation directory = /usr/lib/firefox-3.0
Proceed with the installation? (y/n/q):
输入y，回车，就会开始安装。
安装完成后，程序会继续询问你是不是还需要为其他浏览器安装，回答n后回车即可。
到此，flash就安装完成咯。
