Linux中shell脚本练习-编程知识

1.猜数字

2.批量创建用户

3.监控网卡Receive Transmit 数据的变化

4.部署Linux

5.系统性能检测脚本

6.分区脚本

7.数据库脚本

1.猜数字

随机数的生成

使用环境变量RANDOM，范围是0～32767

编写guest.sh，实现以下功能：
1、随机生成一个1～20的数字；
2、每猜一次都会提示目前数字与随机数的大小关系，直到用户猜对提示成功；
3、当用户输入exit时，退出脚本。

#!/bin/bash
let num=$RANDOM%20
while true
doread -p "Please input lucky number:" dateif [ $date = $num  ]thenecho "yes !!"breakelif [ "$date" = "exit"  ]thenecho "bye!"exitelif [ $date -gt $num  ]thenecho "too big"elseecho "too small"fi
done

2.批量创建用户

执行users_create.sh userlist passlist
建立userlist中的用户
设定userlist中的密码为paslist中的密码
当脚本后面跟得文件个数不足两个时报错
当文件行数不一致时报错
当文件不存在时报错
当用户存在时报错

#!/bin/bash
if [ "$#" -lt "2" ]
thenecho "error: 文件不足两个"
elif [ ! -e "$1" ]
thenecho "error: $1 文件不存在"
elif [ ! -e "$2" ]
thenecho "error: $2 文件不存在"
elif [ "`awk 'END{print NR}' $1 `" != "`awk 'END{print NR}' $2 `" ]
thenecho "error: 文件行数不一致"elseLINES=`awk 'END{print NR}' $1 `for LINE in `seq 1 $LINES`doUSERNAME=`sed -n ${LINE}p $1 `PASSWORD=`sed -n ${LINE}p $2 `if id "$USERNAME" &> /dev/nullthenecho "error: $USERNAME 该用户已存在"elseuseradd $USERNAMEecho $PASSWORD | passwd --stdin $USERNAME  &> /dev/nullecho "$USERNAME  $PASSWORD 用户创建成功"fidone
fi

3.监控网卡Receive Transmit 数据的变化

#!/bin/bash
if [ -z "$1"  ]
thenecho Please input net device following $0 !!
elif ifconfig $1 &> /dev/null
thenwhile truedoRS1=$(awk "/$1/{print \$2}" /proc/net/dev)TR1=$(awk "/$1/{print \$10}" /proc/net/dev)sleep 1RS2=$(awk "/$1/{print \$2}" /proc/net/dev)TR2=$(awk "/$1/{print \$10}" /proc/net/dev)echo -ne "Receice: $[$RS2-$RS1]byte/s, Transmit: $[$TR2-$TR1]byte/s"echo -ne "\r"done
elseecho no
fi

4.部署Linux

1.修改IP

2.添加本机解析

3.修改主机名

#!/bin/bash
if  [ -z "1" ]
thenecho Please input ID following $0 !!
elif echo $1 | grep -E '^[[:digit:]]{1,}$'
thenecho Please input A number following $0 !!hostnamectl set-hostname vm$1echo 192.168.67.$1 vm$1 >> /etc/hostsDEV_COUNT=`nmcli device show | awk 'BEGIN{N=0}/GENERAL.DEVICE/&&!/lo/{N++}END{ print N}'`[ "$DEV_COUNT" -gt "1" ]&&{for DEVICE in `nmcli device show | awk '/GENERAL.DEVICE/&&!/lo/{ print $2}'`doread -p "Do you want set $DEVICE: " STATEcase $STATE inyes|YES|y|Y)read -p "Please input ip address: " IP
cat > /etc/sysconfig/network-scripts/ifcfg-$DEVICE <<EOF
BOOTPROTO=none
NAME=$DEVICE
DEVICE=$DEVICE
ONBOOT=yes
IPADDR=$IP
PREFIX=24
DNS1=114.114.114.114
EOF;;no|NO|n|N);;*)esacnmcli connection reloadnmcli connection up $DEVICEdone
}
fi

5.系统性能检测脚本

执行check_upload.sh
显示效果如下：
cpu 实际用量%
mem 实际用量%

#!/bin/bash
echo cpu  实际用量 $(printf '%0.2f' `ps ax -o %cpu | awk 'BEGIN{CPU=0}{CPU+=$1}END{print CPU}' `)%
echo mem  实际用量 $(printf '%0.2f' `ps ax -o %mem | awk 'BEGIN{MEM=0}{MEM+=$1}END{print MEM}' `)%

6.分区脚本

用脚本在当前系统添加一个swap分区
swap分区大小为500M并开机自动激活分区

#!/bin/bash
if [ -z "$1" ]
thenecho "error: please input device for swap"
elif [ "$USER" != "root" ]
thenecho "error: please run $0 with root!!"
else[ ! -b "$1" ] && {echo "$1 is not block device"exit}
fi
/usr/bin/expect <<EOF
spawn  fdisk $1
expect {"Command" {send "n\r"}
}
expect {"Select" { send "\r";exp_continue }"Partition number" { send "\r";exp_continue }"First sector" { send "\r";exp_continue }"Last sector" { send "+500M\r";exp_continue }"signature" { send "yes\r";exp_continue }"Command" { send "wq\r" }}expect eof
EOFfdisk $1 <<EOF
t82
wq
EOFDISK=`fdisk -l $1 | awk 'END{print $1}'`
mkswap $DISKgrep ^$DISK /etc/fstab &&{swapon -a
}  || {echo "$DISK swap swap defaults 0 0 " >> /etc/fstabswapon -a
}

7.数据库脚本

执行db_dump.sh westos（数据库密码）
脚本执行后会备份数据库中所有库到 /mnt/mysqldump目录中
备份文件的名称为库名称.sql 当此文件存在时进行如下判断
输入S跳过备份
输入B备份库名称.sql 到库名称_backup.sql
输入O时，覆盖源文件

#!/bin/bash
if [ -z "$1" ]
thenecho "Please input password for mysql !"exit
firpm -q mariadb-server &> /dev/null || {dnf install mariadb-server.x86_64 -y 
}systemctl status mariadb.service | grep "running" &> /dev/null || {systemctl start mariadb.service &> /dev/null
}DBS=`mysql -uroot -p$1 -EN -e "SHOW DATABASES;" 2> /dev/null | grep -vE "row|_schema$"`
##设定DB并且检测数据库密码是否正确 -N 去表头 2> 过滤错误输出
if [ "$?" -ne "0" ]
thenecho "Error: Wrong password for db !"
elsemkdir -p /mnt/mysqldump												##建立多层目录for DBNAME in $DBSdoif [ ! -e "/mnt/mysqldump/$DBNAME.sql" ]							##如果不存在thenmysqldump -uroot -p$1  $DBNAME > /mnt/mysqldump/$DBNAME.sql		##备份else																##如果存在echo "/mnt/mysqldump/$DBNAME.sql is exist !"						##显示已存在echo "You can do action: [S]kip [B]ackup [O]verwrite [E]xit"		##提示下一步动作while truedoread -p "Please input action: " ACTIONcase $ACTION ins|S|skip|Skip)												##直接跳过break;;b|B|backup|Backup)											##将已存在的备份文件改名并重新备份mv /mnt/mysqldump/$DBNAME.sql /mnt/mysqldump/${DBNAME}_backup_`date +%m%d%h`.sqlmysqldump -uroot -p$1 $DBNAME > /mnt/mysqldump/$DBNAME.sqlbreak;;o|O|overwrite|Overwrite)										##覆盖已存在的备份文件mysqldump -uroot -p$1 $DBNAME > /mnt/mysqldump/$DBNAME.sqlbreak;;e|E|exit|Exit)												##退出break;;*)echo Wrong action !!											##错误指令continueesacdonefidone
fi