shell脚本实践之九五二八（一）

2019.08.28

 1. 编写一个shell脚本，判断192.168.1.0/24络内，在线的ip有哪些，能ping通就代表在线。

[root@shell scripts]# vim 001-judge_ip.sh
#!/bin/bash

for ip in $(seq 254)
do
  ping -c 1 192.168.1.$ip &>/dev/null
  if [ $? = 0 ];then
    echo 192.168.1.$ip is online
  fi
done

 

2019.08.29

 1. 编写一个shell脚本，批量创建5个用户并且创建8位随机密码。

# 第一种方法
[root@shell scripts]# vim 002-creat_user.sh
#!/bin/bash

for u in user{01..05}
do
  useradd $u
  PWD=`tr -dc '0-z' </dev/urandom | head -c 8`
  echo -e "user:$u
password:$PWD" >>/tmp/user.txt
  echo "$u:$PWD" | chpasswd
done
# 第二种方法
[root@shell scripts]# vim 002-creat_user.sh
#!/bin/bash

for u in oldboy{01..05}
do
  useradd $u
  for p in `echo $RANDOM | md5sum | cut -c 1-8`
  do
    echo -e "user:$u
password:$p" >>/tmp/user.txt
    echo "$u:$p" | chpasswd
  done
done

 

2019.08.30

 1. 写一个批量分发公钥的脚本。

# CentOS 7.x版本
[root@shell scripts]# vim batch.sh
#!/bin/bash

PWD=接收公钥主机的密码

rm -rf /root/.ssh/id_dsa*
ssh-keygen -t dsa -f /root/.ssh/id_dsa -P '' -q

for ip in $*
do
  sshpass -p $PWD ssh-copy-id -i /root/.ssh/id_dsa.pub -o StrictHostKeyChecking=no $ip &>/dev/null
  if [ $? != 0 ];then
    echo -e "
----- $ip distribution of failure -----
" 
    continue
  fi
done

 

2019.09.01

 1. 猜数字游戏，60以内的整数。

[root@shell scripts]# vim guess_number.sh
#!/bin/bash

RAN=$((RANDOM%61))
COUNT=0

while true
do
  read -p 'Please enter a number：' num
  ((COUNT++))
  expr $num + 0 &>/dev/null
  if [ $? -ne 0 -o $num -gt 60 ];then
    echo 'Invalid parameter,Please enter an integer within 60'
  else
    if [ $num -eq $RAN ];then
      echo "Bingo!You guessed right,$COUNT times"
      exit
    elif [ $num -gt $RAN ];then
      echo 'too big'
    else
      echo 'too small'
    fi
  fi
done

 

2019.11.04

 1. 找出目录中大于200M的日志文件并压缩，压缩文件仍保留在原目录中，压缩完成后删除原日志文件。

[root@shell scripts]# vim find.sh
#!/bin/bash

for file in `find /data/logs -type f -name '*.log' -size +200M`
do
        filename=`basename  ${file}`
        dirname=`dirname  ${file}`
        cd ${dirname}
        tar -zcPf ${filename}.tar.gz ${filename} --remove-files
done

 

2019.12.06

 1. CentOS 6&7 初始化脚本

# 首先需要启动你的网卡（根据实际的网卡名称，可用ip a查看网卡名）。
[root@shell scripts]# ifup eth0
[root@shell scripts]# cat optimize.sh
#!/bin/bash

# Author：JingXue
# CreateDate：2019/12/06
# Description：CentOS 6&7 初始化脚本

NET=`ip a | egrep 'ens|eth0' | head -1 | awk -F '[ :]+' '{print $2}'`
VERSION=`cat /etc/redhat-release | awk -F '.' '{print $1}' | awk '{print $NF}'`

set_network () {
        egrep 'ONBOOT=yes|ONBOOT="yes"' /etc/sysconfig/network-scripts/ifcfg-${NET} &>/dev/null || sed -i 's/ONBOOT.*/ONBOOT=yes/g' /etc/sysconfig/network-scripts/ifcfg-${NET}
        grep persistent /etc/rc.local &>/dev/null || echo '>/etc/udev/rules.d/70-persistent-net.rules' >>/etc/rc.local            # 初始化模板时需要执行
        egrep 'HWADDR|UUID' /etc/sysconfig/network-scripts/ifcfg-${NET} &>/dev/null && sed -ri '/HWADDR|UUID/d' /etc/sysconfig/network-scripts/ifcfg-${NET}   # 初始化模板时需执行
}

set_yum_repos() {                       # 阿里云主机可省此步骤
    grep aliyun CentOS-Base.repo.bak &>/dev/null
    if [ $? != 0 ];then
        mv /etc/yum.repos.d/CentOS-Base.repo{,.bak}
        if [ ${VERSION} = 6 ];then
            curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
        elif [ ${VERSION} = 7 ];then
            curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
        fi
    else
        continue
    fi
}

set_public() {
    yum clean all && yum makecache fast
    yum -y update
    yum -y install epel-release
    yum -y install tree lrzsz nmap nc telnet vim wget lsof net-tools bash-completion bash-completion-extras psmisc bind-utils sysstat htop yum-utils sshpass git expect unzip
    grep 'rm=' /etc/bashrc &>/dev/null || echo "alias rm='rm is not used'" >>/etc/bashrc
    grep 'PS1=' /etc/profile &>/dev/null || echo 'export PS1="[e[37;40m][[e[31;40m]u[e[37;40m]@h [e[33;40m]W[e[0m]]\$ "' >>/etc/profile
    source /etc/profile /etc/bashrc
    grep 'SELINUX=disabled' /etc/selinux/config &>/dev/null || sed -i.bak 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/config      # 阿里云ECS可省
    setenforce 0        # 阿里云ECS可省
    grep 'time sync' /var/spool/cron/root &>/dev/null || echo -e '# time sync
*/5 * * * * /usr/sbin/ntpdate ntp1.aliyun.com &>/dev/null' >>/var/spool/cron/root    # 阿里云ECS可省
}

set_limits() {
    grep 'nofile 65536' /etc/security/limits.conf &>/dev/null || echo -e '* soft nofile 65536
* hard nofile 65536' >>/etc/security/limits.conf
cat >>/etc/sysctl.conf <<EOF
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 30
vm.max_map_count=262144
EOF
    sysctl -p
    if [ ${VERSION} = 6 ];then
        sed -i 's/1024/4096/g' /etc/security/limits.d/90-nproc.conf
    else
        continue
    fi
}

set_hostname() {
    read -p '请设置主机名：' HOSTNAME
    if [ ${VERSION} = 6 ];then
        hostname ${HOSTNAME}
        sed -i.bak "s/^HOST.*/HOSTNAME=${HOSTNAME}/" /etc/sysconfig/network
        sed -i.bak "s/localhost.localdomain/${HOSTNAME}/" /etc/hosts
    elif [ ${VERSION} = 7 ];then
        hostnamectl set-hostname ${HOSTNAME}
        sed -i.bak "s/localhost.localdomain/${HOSTNAME}/" /etc/hosts
    fi

}

set_services() {
    if [ ${VERSION} = 6 ];then
        service iptables stop
        service postfix stop
        chkconfig iptables off
        chkconfig postfix off
        chkconfig network on
        chkconfig sshd on
        chkconfig crond on
    elif [ ${VERSION} = 7 ];then
        systemctl start sshd.service network.service crond.service
        systemctl enable sshd.service network.service crond.service
        systemctl stop NetworkManager firewalld.service postfix.service
        systemctl disable NetworkManager firewalld.service postfix.service
    fi
}

set_network
set_yum_repos
set_public
set_limits
set_hostname
set_services

echo -e "33[31m*******************系统初始化完毕，将在20s后重启!!!*******************33[0m"
sleep 20s && reboot

 
 

未完待续......