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andrewji8

Being towards death

Heed not to the tree-rustling and leaf-lashing rain, Why not stroll along, whistle and sing under its rein. Lighter and better suited than horses are straw sandals and a bamboo staff, Who's afraid? A palm-leaf plaited cape provides enough to misty weather in life sustain. A thorny spring breeze sobers up the spirit, I feel a slight chill, The setting sun over the mountain offers greetings still. Looking back over the bleak passage survived, The return in time Shall not be affected by windswept rain or shine.
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9 practical shell scripts, recommended for bookmarking!

  1. DoS Attack Prevention (Automatically Blocking Attacking IP)
#!/bin/bash
DATE=$(date +%d/%b/%Y:%H:%M)
LOG_FILE=/usr/local/nginx/logs/demo2.access.log
ABNORMAL_IP=$(tail -n5000 $LOG_FILE |grep $DATE |awk '{a[$1]++}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 $IP -j DROP
        echo "$(date +'%F_%T') $IP" >> /tmp/drop_ip.log
    fi
done
  1. Linux System Alert Script
# yum install mailx
# vi /etc/mail.rc
set from=baojingtongzhi@163.com smtp=smtp.163.com
set smtp-auth-user=baojingtongzhi@163.com smtp-auth-password=123456
set smtp-auth=login
  1. MySQL Database Backup Single Loop
#!/bin/bash
DATE=$(date +%F_%H-%M-%S)
HOST=localhost
USER=backup
PASS=123.com
BACKUP_DIR=/data/db_backup
DB_LIST=$(mysql -h$HOST -u$USER -p$PASS -s -e "show databases;" 2>/dev/null |egrep -v "Database|information_schema|mysql|performance_schema|sys")

for DB in $DB_LIST; do
    BACKUP_NAME=$BACKUP_DIR/${DB}_${DATE}.sql
    if ! mysqldump -h$HOST -u$USER -p$PASS -B $DB > $BACKUP_NAME 2>/dev/null; then
        echo "$BACKUP_NAME Backup Failed!"
    fi
done
  1. MySQL Database Backup Multiple Loops
#!/bin/bash
DATE=$(date +%F_%H-%M-%S)
HOST=localhost
USER=backup
PASS=123.com
BACKUP_DIR=/data/db_backup
DB_LIST=$(mysql -h$HOST -u$USER -p$PASS -s -e "show databases;" 2>/dev/null |egrep -v "Database|information_schema|mysql|performance_schema|sys")

for DB in $DB_LIST; do
    BACKUP_DB_DIR=$BACKUP_DIR/${DB}_${DATE}
    [ ! -d $BACKUP_DB_DIR ] && mkdir -p $BACKUP_DB_DIR &>/dev/null
    TABLE_LIST=$(mysql -h$HOST -u$USER -p$PASS -s -e "use $DB;show tables;" 2>/dev/null)
    for TABLE in $TABLE_LIST; do
        BACKUP_NAME=$BACKUP_DB_DIR/${TABLE}.sql
        if ! mysqldump -h$HOST -u$USER -p$PASS $DB $TABLE > $BACKUP_NAME 2>/dev/null; then
            echo "$BACKUP_NAME Backup Failed!"
        fi
    done
done
  1. Nginx Access Log Split by Day
#!/bin/bash
LOG_DIR=/usr/local/nginx/logs
YESTERDAY_TIME=$(date -d "yesterday" +%F)
LOG_MONTH_DIR=$LOG_DIR/$(date +"%Y-%m")
LOG_FILE_LIST="default.access.log"

for LOG_FILE in $LOG_FILE_LIST; do
    [ ! -d $LOG_MONTH_DIR ] && mkdir -p $LOG_MONTH_DIR
    mv $LOG_DIR/$LOG_FILE $LOG_MONTH_DIR/${LOG_FILE}_${YESTERDAY_TIME}
done

kill -USR1 $(cat /var/run/nginx.pid)
  1. Nginx Access Log Analysis Script
#!/bin/bash
# Log Format: $remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" "$http_x_forwarded_for"
LOG_FILE=$1
echo "Top 10 Most Visited IPs"
awk '{a[$1]++}END{print "UV:",length(a);for(v in a)print v,a[v]}' $LOG_FILE |sort -k2 -nr |head -10
echo "----------------------"

echo "Top IPs Visited in a Time Range"
awk '$4>="[01/Dec/2018:13:20:25" && $4<="[27/Nov/2018:16:20:49"{a[$1]++}END{for(v in a)print v,a[v]}' $LOG_FILE |sort -k2 -nr|head -10
echo "----------------------"

echo "Top 10 Most Visited Pages"
awk '{a[$7]++}END{print "PV:",length(a);for(v in a){if(a[v]>10)print v,a[v]}}' $LOG_FILE |sort -k2 -nr
echo "----------------------"

echo "Count of Page Status Codes"
awk '{a[$7" "$9]++}END{for(v in a){if(a[v]>5)print v,a[v]}}'
  1. Real-Time Network Traffic Monitoring Script
#!/bin/bash
NIC=$1
echo -e " In ------ Out"
while true; do
    OLD_IN=$(awk '$0~"'$NIC'"{print $2}' /proc/net/dev)
    OLD_OUT=$(awk '$0~"'$NIC'"{print $10}' /proc/net/dev)
    sleep 1
    NEW_IN=$(awk  '$0~"'$NIC'"{print $2}' /proc/net/dev)
    NEW_OUT=$(awk '$0~"'$NIC'"{print $10}' /proc/net/dev)
    IN=$(printf "%.1f%s" "$((($NEW_IN-$OLD_IN)/1024))" "KB/s")
    OUT=$(printf "%.1f%s" "$((($NEW_OUT-$OLD_OUT)/1024))" "KB/s")
    echo "$IN $OUT"
    sleep 1
done
  1. Server System Configuration Initialization Script
#/bin/bash
# Set Timezone and Synchronize Time
ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
if ! crontab -l |grep ntpdate &>/dev/null ; then
    (echo "* 1 * * * ntpdate time.windows.com >/dev/null 2>&1";crontab -l) |crontab
fi

# Disable SELinux
sed -i '/SELINUX/{s/permissive/disabled/}' /etc/selinux/config

# Disable Firewall
if egrep "7.[0-9]" /etc/redhat-release &>/dev/null; then
    systemctl stop firewalld
    systemctl disable firewalld
elif egrep "6.[0-9]" /etc/redhat-release &>/dev/null; then
    service iptables stop
    chkconfig iptables off
fi

# Show Command History with Timestamp
if ! grep HISTTIMEFORMAT /etc/bashrc; then
    echo 'export HISTTIMEFORMAT="%F %T `whoami` "' >> /etc/bashrc
fi

# SSH Timeout
if ! grep "TMOUT=600" /etc/profile &>/dev/null; then
    echo "export TMOUT=600" >> /etc/profile
fi

# Disable Root Remote Login
sed -i 's/#PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config

# Disable Cron Job Email Notification
sed -i 's/^MAILTO=root/MAILTO=""/' /etc/crontab

# Set Maximum Open Files
if ! grep "* soft nofile 65535" /etc/security/limits.conf &>/dev/null; then
    cat >> /etc/security/limits.conf << EOF
    * soft nofile 65535
    * hard nofile 65535
EOF
fi

# System Kernel Optimization
cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_tw_buckets = 20480
net.ipv4.tcp_max_syn_backlog = 20480
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_fin_timeout = 20
EOF

# Reduce SWAP Usage
echo "0" > /proc/sys/vm/swappiness

# Install System Performance Analysis Tools and Others
yum install gcc make autoconf vim sysstat net-tools iostat if
  1. Monitor Disk Utilization of 100 Servers Script
#!/bin/bash
HOST_INFO=host.info
for IP in $(awk '/^[^#]/{print $1}' $HOST_INFO); do
    USER=$(awk -v ip=$IP 'ip==$1{print $2}' $HOST_INFO)
    PORT=$(awk -v ip=$IP 'ip==$1{print $3}' $HOST_INFO)
    TMP_FILE=/tmp/disk.tmp
    ssh -p $PORT $USER@$IP 'df -h' > $TMP_FILE
    USE_RATE_LIST=$(awk 'BEGIN{OFS="="}/^\/dev/{print $NF,int($5)}' $TMP_FILE)
    for USE_RATE in $USE_RATE_LIST; do
        PART_NAME=${USE_RATE%=*}
        USE_RATE=${USE_RATE#*=}
        if [ $USE_RATE -ge 80 ]; then
            echo "Warning: $PART_NAME Partition usage $USE_RATE%!"
        fi
    done
done
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