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本章目錄:
12.11 屏蔽網(wǎng)站訪問頻繁的IP
1)屏蔽每分鐘訪問超過200的IP
方法1:以Nginx日志作為測試
DATE=$(date +%d/%b/%Y:%H:%M) ABNORMAL_IP=$(tail -n5000 access.log |grep $DATE |awk '{a[$1]++}END{for(i in a)if(a[i]>100)print i}') #先tail防止文件過大,讀取慢,數(shù)字可調(diào)整每分鐘最大的訪問量。awk不能直接過濾日志,因為包含特殊字符。 for IP in $ABNORMAL_IP; do if [ $(iptables -vnL |grep -c "$IP") -eq 0 ]; then iptables -I INPUT -s $IP -j DROP fi done
方法2:通過建立連接數(shù)
ABNORMAL_IP=$(netstat -an |awk '$4~/:80$/ && $6~/ESTABLISHED/{gsub(/:[0-9]+/,"",$5);{a[$5]++}}END{for(i in a)if(a[i]>100)print i}') #gsub是將第五列(客戶端IP)的冒號和端口去掉 for IP in $ABNORMAL_IP; do if [ $(iptables -vnL |grep -c "$IP") -eq 0 ]; then iptables -I INPUT -s $IP -j DROP fi done
2)屏蔽每分鐘SSH暴力破解超過10次的IP
方法1:通過lastb獲取登錄狀態(tài):
DATE=$(date +"%a %b %e %H:%M") #星期月天時分 %e單數(shù)字時顯示7,而%d顯示07 ABNORMAL_IP=$(lastb |grep "$DATE" |awk '{a[$3]++}END{for(i in a)if(a[i]>10)print i}') for IP in $ABNORMAL_IP; do if [ $(iptables -vnL |grep -c "$IP") -eq 0 ]; then iptables -I INPUT -s $IP -j DROP fi done
方法2:通過日志獲取登錄狀態(tài)
DATE=$(date +"%b %d %H") ABNORMAL_IP="$(tail -n10000 /var/log/auth.log |grep "$DATE" |awk '/Failed/{a[$(NF-3)]++}END{for(i in a)if(a[i]>5)print i}')" for IP in $ABNORMAL_IP; do if [ $(iptables -vnL |grep -c "$IP") -eq 0 ]; then iptables -A INPUT -s $IP -j DROP echo "$(date +"%F %T") - iptables -A INPUT -s $IP -j DROP" >>~/ssh-login-limit.log fi done
12.12 判斷輸入是否為IP
方法1:
function check_ip(){ IP=$1 VALID_CHECK=$(echo $IP|awk -F. '$1<=255&&$2<=255&&$3<=255&&$4<=255{print "yes"}') if echo $IP|grep -E "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$">/dev/null; then if [ $VALID_CHECK == "yes" ]; then echo "$IP available." else echo "$IP not available!" fi else echo "Format error!" fi } check_ip 192.168.1.1 check_ip 256.1.1.1
方法2:
function check_ip(){ IP=$1 if [[ $IP =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then FIELD1=$(echo $IP|cut -d. -f1) FIELD2=$(echo $IP|cut -d. -f2) FIELD3=$(echo $IP|cut -d. -f3) FIELD4=$(echo $IP|cut -d. -f4) if [ $FIELD1 -le 255 -a $FIELD2 -le 255 -a $FIELD3 -le 255 -a $FIELD4 -le 255 ]; then echo "$IP available." else echo "$IP not available!" fi else echo "Format error!" fi } check_ip 192.168.1.1 check_ip 256.1.1.1
增加版:加個死循環(huán),如果IP可用就退出,不可用提示繼續(xù)輸入,并使用awk判斷
function check_ip(){ local IP=$1 VALID_CHECK=$(echo $IP|awk -F. '$1<=255&&$2<=255&&$3<=255&&$4<=255{print "yes"}') if echo $IP|grep -E "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" >/dev/null; then if [ $VALID_CHECK == "yes" ]; then return 0 else echo "$IP not available!" return 1 fi else echo "Format error! Please input again." return 1 fi } while true; do read -p "Please enter IP: " IP check_ip $IP [ $? -eq 0 ] && break || continue done
12.13 判斷輸入是否為數(shù)字
方法1: if [[ $1 =~ ^[0-9]+$ ]]; then echo "Is Number." else echo "No Number." fi 方法2: if [ $1 -gt 0 ] 2>/dev/null; then echo "Is Number." else echo "No Number." fi
方法3:
echo $1 |awk '{print $0~/^[0-9]+$/?"Is Number.":"No Number."}' #三目運算符 12.14 找出包含關(guān)鍵字的文件 DIR=$1 KEY=$2 for FILE in $(find $DIR -type f); do if grep $KEY $FILE &>/dev/null; then echo "--> $FILE" fi done
12.15 監(jiān)控目錄,將新創(chuàng)建的文件名追加到日志中
需安裝inotify-tools軟件包。
#!/bin/bash MON_DIR=/opt inotifywait -mq --format %f -e create $MON_DIR |\ while read files; do echo $files >> test.log done 12.16 多個網(wǎng)卡選擇 function local_nic() { local NUM ARRAY_LENGTH NUM=0 for NIC_NAME in $(ls /sys/class/net|grep -vE "lo|docker0"); do NIC_IP=$(ifconfig $NIC_NAME |awk -F'[: ]+' '/inet addr/{print $4}') if [ -n "$NIC_IP" ]; then NIC_IP_ARRAY[$NUM]="$NIC_NAME:$NIC_IP" #將網(wǎng)卡名和對應(yīng)IP放到數(shù)組 let NUM++ fi done ARRAY_LENGTH=${#NIC_IP_ARRAY[*]} if [ $ARRAY_LENGTH -eq 1 ]; then #如果數(shù)組里面只有一條記錄說明就一個網(wǎng)卡 NIC=${NIC_IP_ARRAY[0]%:*} return 0 elif [ $ARRAY_LENGTH -eq 0 ]; then #如果沒有記錄說明沒有網(wǎng)卡 echo "No available network card!" exit 1 else #如果有多條記錄則提醒輸入選擇 for NIC in ${NIC_IP_ARRAY[*]}; do echo $NIC done while true; do read -p "Please enter local use to network card name: " INPUT_NIC_NAME COUNT=0 for NIC in ${NIC_IP_ARRAY[*]}; do NIC_NAME=${NIC%:*} if [ $NIC_NAME == "$INPUT_NIC_NAME" ]; then NIC=${NIC_IP_ARRAY[$COUNT]%:*} return 0 else COUNT+=1 fi done echo "Not match! Please input again." done fi } local_nic
如果有只有一個網(wǎng)卡就不選擇。
12.17 查看網(wǎng)卡實時流量
#!/bin/bash # Description: Only CentOS6 traffic_unit_conv() { local traffic=$1 if [ $traffic -gt 1024000 ]; then printf "%.1f%s" "$(($traffic/1024/1024))" "MB/s" elif [ $traffic -lt 1024000 ]; then printf "%.1f%s" "$(($traffic/1024))" "KB/s" fi } NIC=$1 echo -e " In ------ Out" while true; do OLD_IN=$(awk -F'[: ]+' '$0~"'$NIC'"{print $3}' /proc/net/dev) OLD_OUT=$(awk -F'[: ]+' '$0~"'$NIC'"{print $11}' /proc/net/dev) sleep 1 NEW_IN=$(awk -F'[: ]+' '$0~"'$NIC'"{print $3}' /proc/net/dev) NEW_OUT=$(awk -F'[: ]+' '$0~"'$NIC'"{print $11}' /proc/net/dev) IN=$(($NEW_IN-$OLD_IN)) OUT=$(($NEW_OUT-$OLD_OUT)) echo "$(traffic_unit_conv $IN) $(traffic_unit_conv $OUT)" sleep 1 done # 也可以通過ficonfig命令獲取收發(fā)流量 while true; do OLD_IN=$(ifconfig $NIC |awk -F'[: ]+' '/bytes/{print $4}') OLD_OUT=$(ifconfig $NIC |awk -F'[: ]+' '/bytes/{print $9}') sleep 1 NEW_IN=$(ifconfig $NIC |awk -F'[: ]+' '/bytes/{print $4}') NEW_OUT=$(ifconfig $NIC |awk -F'[: ]+' '/bytes/{print $9}') IN=$(($NEW_IN-$OLD_IN)) OUT=$(($NEW_OUT-$OLD_OUT)) echo "$(traffic_unit_conv $IN) $(traffic_unit_conv $OUT)" sleep 1 done
12.18 MySQL數(shù)據(jù)庫備份
#!/bin/bash DATE=$(date +%F_%H-%M-%S) HOST=192.168.1.120 DB=test USER=bak PASS=123456 MAIL="zhangsan@example.com lisi@example.com" BACKUP_DIR=/data/db_backup SQL_FILE=${DB}_full_$DATE.sql BAK_FILE=${DB}_full_$DATE.zip cd $BACKUP_DIR if mysqldump -h$HOST -u$USER -p$PASS --single-transaction --routines --triggers -B $DB > $SQL_FILE; then zip $BAK_FILE $SQL_FILE && rm -f $SQL_FILE if [ ! -s $BAK_FILE ]; then echo "$DATE 內(nèi)容" | mail -s "主題" $MAIL fi else echo "$DATE 內(nèi)容" | mail -s "主題" $MAIL fi find $BACKUP_DIR -name '*.zip' -ctime +14 -exec rm {} \;
12.19 Nginx啟動腳本
#!/bin/bash # Description: Only support RedHat system . /etc/init.d/functions WORD_DIR=/data/project/nginx1.10 DAEMON=$WORD_DIR/sbin/nginx CONF=$WORD_DIR/conf/nginx.conf NAME=nginx PID=$(awk -F'[; ]+' '/^[^#]/{if($0~/pid;/)print $2}' $CONF) if [ -z "$PID" ]; then PID=$WORD_DIR/logs/nginx.pid else PID=$WORD_DIR/$PID fi stop() { $DAEMON -s stop sleep 1 [ ! -f $PID ] && action "* Stopping $NAME" /bin/true || action "* Stopping $NAME" /bin/false } start() { $DAEMON sleep 1 [ -f $PID ] && action "* Starting $NAME" /bin/true || action "* Starting $NAME" /bin/false } reload() { $DAEMON -s reload } test_config() { $DAEMON -t } case "$1" in start) if [ ! -f $PID ]; then start else echo "$NAME is running..." exit 0 fi ;; stop) if [ -f $PID ]; then stop else echo "$NAME not running!" exit 0 fi ;; restart) if [ ! -f $PID ]; then echo "$NAME not running!" start else stop start fi ;; reload) reload ;; testconfig) test_config ;; status) [ -f $PID ] && echo "$NAME is running..." || echo "$NAME not running!" ;; *) echo "Usage: $0 {start|stop|restart|reload|testconfig|status}" exit 3 ;; esac
12.20 選擇SSH連接主機
寫一個配置文件保存被監(jiān)控主機SSH連接信息,文件內(nèi)容格式:主機名 IP User Port
#!/bin/bash PS3="Please input number: " HOST_FILE=host while true; do select NAME in $(awk '{print $1}' $HOST_FILE) quit; do [ ${NAME:=empty} == "quit" ] && exit 0 IP=$(awk -v NAME=${NAME} '$1==NAME{print $2}' $HOST_FILE) USER=$(awk -v NAME=${NAME} '$1==NAME{print $3}' $HOST_FILE) PORT=$(awk -v NAME=${NAME} '$1==NAME{print $4}' $HOST_FILE) if [ $IP ]; then echo "Name: $NAME, IP: $IP" ssh -o StrictHostKeyChecking=no -p $PORT -i id_rsa $USER@$IP # 密鑰登錄 break else echo "Input error, Please enter again!" break fi done done
本章寫的Shell腳本例子都比較實用,在面試題中也經(jīng)常出現(xiàn),希望大家參考著多動手寫寫,不要復制粘貼就拿來跑,這樣是學不會的!有問題請加×××流:323779636(Shell/Python運維開發(fā)群)
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