shell应用

一、倒计时

数学计算

#!/bin/bash
MIN=1
SEC=10
ALL_SEC=$[$MIN*60+$SEC]
for((;ALL_SEC>0;ALL_SEC--))
do
	SHOW_MIN=$[$ALL_SEC/60]
	SHOW_SEC=$[$ALL_SEC%60]
	echo -ne "\r$SHOW_MIN:SHOW_SEC\r"
	sleep 1
done

逻辑判断

#!/bin/bash
read -p "please input the time:" TIME
MIN=`echo $TIME | awk -F : '{print $1}'`
SEC=`echo $TIME` | awk -F : '{print $2}'
while (($MIN>=0))
do
	[ $MIN -eq "0" -a $SEC -eq "0" ] && {
		echo end
		exit
	}
	if [ $SEC -eg "0" ]
	then
		echo -ne "\r$MIN:$SEC\r"
		((SEC--))
		sleep 1
	else
		((MIN--))
		SEC=59
	fi	
done

二、数据备份

#!/bin/bash
if [ ! -e "/var/lib/mysql/mysql.sock" ]
then
	echo "mysql is not running"
	exit 1
elif [ -z $1 ] 
then
	echo "please input the password of db follow $0"
	exit 1
fi
mysql -uroot -p$1 "SHOW DATABASES;" &> /dev/null
if [ $? -ne "0" ]
then
	echo "wrong password for db!!"
	exit 1
fi
[ -e "/mnt/mysqldump" ]  || {
	mkdir /mnt/mysqldump -p
}
ALL_DB=`mysql -uroot -p$1 -NE -e "SHOW DATABASES;" | sed '/*^/d;/schema$/d'`
ACTION_CHOOSE(){
	read -p "please input your action:" ACTION
	case $ACTION in
		S|s|skip)
		;;
		B|b|bacup)
		mv /mnt/mysqldump/${DBNAME}.sql /mnt/mysqldump/${DBNAME}backup.sql
		mysqldump -uroot -p$1 $DBNAME > /mnt/mysqldump/${DBNAME}.sql
		;;
		O|o|overwrite)
		mysqldump -uroot -p$1 $DBNAME > /mnt/mysqldump/${DBNAME}.sql
		;;
		*)
		echo "wrong action,please input s|b|o again"
		ACTION_CHOOSE
	esac
}
for DBNAME in $ALL_DB
do
	if [ -e "/mnt/mysqldump/${DNNAME}.sql" ]
	then
		echo "$DBNAME's backupfile is exist!!"
		echo "you can choose your action:"
		echo  "[S]kip [B]ackup [O]verwrite" 
		ACCTION_CHOOSE
	else
		mysqldump -uroot -p$1 $DBNAME > /mnt/mysqldump/${DBNAME}.sql
	fi
done

三、输入逆转

1、字符反转

法一：

#!/bin/bash
STR=`echo $1 | wc -c `
for((;STR>0;STR--))
do
	echo -n ` echo $1 | cut -c $STR `
done
echo -e "\r"

法二：

#!/bin/bash
echo $1 | rev

字符切片：

a=adfsd
echo ${#a}			字符串的长度
echo ${a:m:n}		显示第a变量m个字符后的n个字符

2、文件反转

tac file			从左后一行开始显示

四、论坛部署

#!/bin/bash
yum install php php-mysql mariadb-server hpptd -y
sed '/\[mysqld\]/a/skip-networking=1' /etc/my.cnf -i /etc/my.cnf
systemctl start httpd mariadb 
systemctl stop firewalld
mysql_secure_installation <<EOF
y
root
root
y
y
y
y
EOF
cd /var/www/html
unzip Discuz_X3.2_SC_UTF8.zip
chmod 777 /var/www/html/upload -R 
firefox http://ip/upload

五、A记录自动获取

#!/bin/bash
AUTO_SSH()
{
	/usr/bin/expect << EOF
	spawn ssh root@$1 hostname
	expect{
		"yes/no" { send "yes\r" ; exp_continue }
		"password" { send "westos\r" }
	}
	expect eof
	EOF
}
for IP in {1..10}
do 
	ping -c1 -w1 172.25.254.$IP &>/dev/null
	if [ $? = "0"]
	then
		echo "`AUTH_SSH 172.25.254.$IP | tali -n 1 | sed 's/^M//g` A 172.25.254.$IP" >>/mnt/ip_host.list 
done