二,日志服务
配置远程日志服务
1，服务器端配置
first,on the log server set up syslogd to accept remote messages,
a, Edit /etc/sysconfig/syslog;
SYSLOGD_OPTIONS="-r -m 0"
b, 重启syslog服务

2，客户端配置
a, append in /etc/syslog.conf the following line
user.* @192.168.0.254
b, 重启syslog服务

3, 测试
logger -i -t yourname "This is a test"

三，XOrg: The X11 Server
1,配置
在3运行级别下运行system-config-display

2,remote X sessions

1>，重定向到其他机器DISPLAY
export DISPLAY=192.168.0.18:0.0
2>, 运行其他机器的图像显示
xhost + (允许全部）
xhost +192.168.0.22 (允许22这台机器)
3>, 恢复本机显示
export DISPLAY=:0.0

四，vnc配置
(1)设置vnc server的访问密码 　
vncpasswd
　　
(2)启动vnc server 　
vncserver

(3)关闭
vncserver -kill :1

vncserver的配置
通过编辑文件$HOME/.vnc/xstartup来启动你喜欢的窗口管理器。使用startkde &来启动KDE，使用gnome-session &来启动GNOME，fvwm2 &来启动FVWM2 。下面是一个例子

(如果不设置，第一次登陆的时候linux 上启动的 vnc server 内定的管理环境是 twm，不好看，也不方便，所以需要修改一下）

#!/bin/sh
# Uncomment the following two lines for normal desktop:
# unset SESSION_MANAGER
# exec /etc/X11/xinit/xinitrc

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
#xterm -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
gnome-session &
#startkde
#twm &

五，cron
used to schedule recurring events
use crontab to edit,install,and view job schedules
syntax
crontab [-u user] file
crontab [-l|-r|-e]

-l lists crontab
-r removes crontab
-e ediats crontab using $EDITOR

controlling access to cron
restrict /allow user access to cron
/etc/cron.allow
/etc/cron.deny

六，The anacron system
anacron runs cron jobs that did not run when the computer is down
assumes computers are not up continually
vital for laptops,desktops,workstations,and other systems that are not up continually
useful for servers that need to be tacken down templrarily

configuration file:/etc/anacrontab
field 1: if the job has not been run in this many days
field 2: wait this number of minutes after reboot and then run it
field 3: job identifier
field 4: the job to run