!/bin/bash

判断172.40.51.0网段有多少是开关机状态
x=0
y=0
for i in seq 254
do
ping -c1 -i0.1 -W1 172.40.51.$i
if [ $? -eq 0 ];then
echo "172.40.51.$i is up"
let x++
else
echo "172.40.51.$i is down"
let y++
fi 
done
echo "开机的有$x个，关机的有$y个。"

1加到100的和
tmp=0
for i in {1..100} 
do
let tmp=$i+$tmp
done
echo "总和:$tmp"

随机猜奖
u=0
num=$[ RANDOM%100+1 ]
while :
do
read -p "[1-100]随即猜：" ca
if [ $ca -eq $num ];then
echo “恭喜中奖”
exit
elif [ $ca -gt $num ];then
echo “猜大了”
else
echo “猜小了”
fi
let u++
done
echo "你猜了$u次"

阉割版if
case "$1" in
-n)
touch $2;;
-e)
vim $2;;
-c)
cat $2;;
-r)
rm -rf $2;;
*)
echo "usage:$0 (-n|-e|-c|-r) 文件名"
esac

加法计算机
tmp=0
while :
do
read -p "请输入一个数[0结束]：" shu
let tmp+=$shu
[ $shu -eq 0 ] && break
done
echo "总和$tmp"

99乘法表
for i in {1..9}
do
for j in seq $i
do
echo -n " $i$j=$[ij]"
done
done

棋盘
for i in {1..10}
do 
for j in {1..10}
do
he=$[i+j]
if [ $[$he%2] -eq 0 ];then
echo -en "\033[45m \033[0m" 
else
echo -en "\033[47m \033[0m"
fi
done
done

用户创建
read -p "请创建用户：" user
echo "必须创建用户"
if [ -z "$user" ];then
while :
do
read -p "请创建用户：" user
[ $? -ne 0 ] && exit
[ -n "$user" ]&& break
done
fi
stty -echo
read -p "请创建密码：" pass
stty echo
pass=${pass:-123456}
useradd "$user"
echo "$pass" |passwd --stdin "$user"

自动 远程操作

rm /root/.ssh/known_host
i=172.25.0.10
expect << EOF
set timeout 30
spawn ssh $i
expext yes {send "yes\n"}
expect password {send "redhat\n"}
expect # {send "touch /qq\n"}
expect # {send "ls\n"} 最后一条不执行
EOF

i=uptime |awk -F: '{print $5}'
if [ $? -eq 0 ];then
echo "CPU 1-15分钟的负载的值是:$i"
fi 
y=ifconfig eth0 |awk '/RX packets/{print $6,$7}'
if [ $? -eq 0 ];then
##echo "RX 接受的数据流量是:$y"
fi 
u=ifconfig eth0 |awk '/TX packets/{print $6,$7}'
if [ $? -eq 0 ];then
echo "TX 发送的数据流量是$u"
fi 
p=free |awk '/Mem:/{print $4}'
if [ $? -eq 0 ];then
echo " 内存剩余："$p"K"
fi 
q=df|awk '/\//{print $4}'
if [ $? -eq 0 ];then
echo "根分区的剩余容量："$q"K"
fi 
w=who |awk '{print $1}'
if [ $? -eq 0 ];then
echo "已登陆的用户：$w"
fi 
a=ps aux |wc -l
if [ $? -eq 0 ];then
echo "进程数量：$a"
fi 
s=rpm -qa |wc -l
if [ $? -eq 0 ];then
echo "已装包数量：$s"
fi

 源码安装ngix

ls / |awk '/nginx.*.gz/'
if [ $? -eq 0 ];then
tar -xf nginx-1.8.0.tar.gz
else
echo "没有nginx-1.8.0.tar.gz包"
exit
fi
cd nginx-1.8.0
yum clean>/dev/null
yum repolist
yum -y install gcc pcre-deve openssl-devel>/dev/null
xi(){
while :
do
echo -ne '\033[42m \033[0m'
sleep 1
done
}
xi &
if [ $? -eq 0 ];then
./configure >/dev/null
fi
make>/dev/null
make install>/dev/null
cd ..
kill $!
i=ls /usr/local/nginx/
if [ $? -eq 0 ];then 
echo OK
else
echo 失败 
fi

nginx的启动服务
case $1 in
start)
/usr/local/nginx/sbin/nginx;;
stop)
/usr/local/nginx/sbin/nginx -s stop;;
restart)
/usr/local/nginx/sbin/nginx -s stop
/usr/local/nginx/sbin/nginx;;
status)
netstat -ntulp |grep nginx;;
*)
echo "请正确输入";;
esac

   拒绝访问失败的ip     

awk '/Failed/{print $11}' /var/log/secure >> ip.txt
if [ -d ip.txt ];then
echo ip.txt没有内容
else
u=cat ip.txt
for i in $u
do
iptables -I INPUT -s 172.25.0.$i -j DROP 
done
fi

     本文转自夜流璃雨 51CTO博客，原文链接：http://blog.51cto.com/13399294/2055319，如需转载请自行联系原作者