//本机ip:192.168.1.6
[root@codfei ~]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
/root/.ssh/id_rsa already exists.
Overwrite (y/n)? y     //以为我是第2 次建立关系所以此处覆盖原来的文件)
Enter passphrase (empty for no passphrase):  //直接回车无须输入密钥)
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
04:37:13:2a:4b:10:af:c1:2b:03:3f:6b:27:ce:b9:62 root@codfei
[root@codfei ~]# cd .ssh/
[root@codfei .ssh]# ll
-rw------- 1 root root 883 Apr 25 17:51 id_rsa
-rw-r--r-- 1 root root 221 Apr 25 17:51 id_rsa.pub
-rw-r--r-- 1 root root 442 Apr 25 17:37 known_hosts

[root@codfei .ssh]# scp id_rsa.pub192.168.1.4:/root/.ssh/192.168.1.6
root@192.168.1.4's password:
id_rsa.pub 100% 221 0.2KB/s 00:00

[root@codfei ~]# cd .ssh/
[root@codfei .ssh]# cat 192.168.1.6 >> authorized_keys

[root@codfei .ssh]# ssh 192.168.1.4
Last login: Wed Aug 8 12:14:42 2007 from 192.168.1.6

####脚本如下#######################
#!/bin/bash
#SCRIPT:df_check.sh
#Writeen by codfei Mon Sep 3 07:25:28 CST 2007
#PURPOSE:This script is used to monitor for full filesystems.
#######################Begining####################
####################
FSMAX="80"
remote_user='root' #####完全可以不用root
remote_ip=(192.168.1.5 192.168.1.6 192.168.1.7 192.168.1.8 192.168.1.9
192.168.1.10 192.168.1.11 192.168.1.12 192.168.1.13 192.168.1.14 ) ---->
# 这里填写你要监控的主机ip
ip_num='0'
while [ "$ip_num" -le "$(expr ${#remote_ip[@]} - 1)" ]
do
read_num='1'
ssh "$remote_user"@"${remote_ip[$ip_num]}" df -h > /tmp/diskcheck_tmp
grep '^/dev/*' /tmp/diskcheck_tmp|awk '{print $5}'|sed 's//%//g' >
/tmp/diskcheck_num_tmp
while [ "$read_num" -le $(wc -l < /tmp/diskcheck_num_tmp) ]
do
size=$(sed -n "$read_num"'p' /tmp/diskcheck_num_tmp)
if [ "$size" -gt "$FSMAX" ]
then
$(grep '^/dev/*' /tmp/diskcheck_tmp|sed -n $read_num'p' >
/tmp/disk_check_mail)
$(echo ${remote_ip[$ip_num]} >> /tmp/disk_check_mail)
$(mail -s "diskcheck_alert" admin < /tmp/disk_check_mail)
fi
read_num=$(expr $read_num + 1)
done
ip_num=$(expr $ip_num + 1)
done
#############over################################
################让脚本每十分钟执行一次#############
在cron 表中加入
0/10 * * * * /home/codfei/diskcheck.sh 2>&1
################################################
##########################
比如， ext2 文件系统， 如果异常死机，开机如何修复文件系统？
如果异常关机，比如断电，通知机房的人开机之后，
我们需要远程修复、检查文件系统
除了/分区之外， 其他的分区：
umount /home
fsck -y /home
/*
/ 分区需要开机之后， 由机房的人来扫描
随后我们再登录并扫描/home 等其他分区
如何查看一个进程所使用的文件句柄？
看这里面 /proc/进程号/fd/的个数就行了
*/

#简单的比如如何查看apache 进程数
[root@localhost fd]# ps -ef|grep httpd|wc -l
1