Shell fourth day homework

1、ping Host test , Check whether the host is alive ;

[[email protected] zuoye]# vim 1.sh
#!/bin/bash
ping -c2 192.168.40.128 &>/dev/null
if [ $? -eq 0 ];then
 echo "is runing"
else
 echo "not runing"
fi
~   

2、 Determine whether a user exists ;

[[email protected] zuoye]# vim 2.sh
#!/bin/bash
read -p "input user name:" name
id $name &>/dev/null
if [ $? -eq 0 ];then
  echo "$name is exist "
else
  echo "$name is not exist"
fi
~   

3、 Determine whether the current kernel major version is 3, And whether the minor version is greater than 10;

[[email protected] zuoye]# vim 3.sh
#!/bin/bash
main="`uname -r |cut -d . -f1`"
sub="`uname -r |cut -d . -f2`"
if [ $main -eq 3 ];then
  if [ "$sub" -gt 10 ];then
    echo "main is 3 and sub more than 10"
  else
    echo "main is 3 but sub less than 10"
  fi
else
  echo "main is not 3"
fi

4、 Judge vsftpd Is the package installed , If not, install automatically ;

[[email protected] zuoye]# vim 4.4.sh
#!/bin/bash
rpm -qa |grep vsftpd
if [ $? -eq 0 ];then
        echo "The vsftpd is install"
else
        yum -y install  vsftpd
        rpm -qa |grep vsftpd

fi

5、 Judge httpd Whether to run ;

[[email protected] zuoye]# vim 4.5.sh
#!/bin/bash
systemctl is-active httpd.service &>/dev/null
if [ $? -eq 0 ];then
        echo "httpd is runing "
else
        echo "httpd is not runing"
fi

6、 Determine whether the specified host can ping through , You have to use $1 Variable ;

[[email protected] zuoye]# vim 4.6.sh
#!/bin/bash
ping -c2 $1 &>/dev/null
if [ $? -eq 0 ];then
        echo "this ip is up"
else
        echo "this ip is down"
fi

7、 Alarm script , Requirements are as follows ：
The remaining space in the root partition is less than 20%
Memory used space is greater than 80%
To the user alice Send alarm email
coordination crond Every time 5 Check every minute

[[email protected] zuoye]# vim 4.7.1.sh 
#!/bin/bash
sy=`df -h | grep -w / |awk {'print $5'}|tr -d %`
memory_user=`free -m|grep Mem|awk {'print $3'}`
memory_total=`free -m|grep Mem|awk {'print $2'}`
memory=`echo $memory_user*100/$memory_total|bc`
if [ "$user -gt 80" -o "$memory -gt 80" ];then
       echo "your / use $sy%, your mem use $memory%" |mail -s "warning" root
fi

8、 Determine whether the user input is a number , If it is a number, judge whether the number is greater than 10;

[[email protected] zuoye]# vim 4.8.sh 
#!/bin/bash
read -p "please input anumber :" num
expr 1 + $num
if [ $? -eq 0  ];then
        if [ $num -gt 10 ];then
                echo "Is nmuber and the number more than 10"
        else
                echo "Is number but the number less than 10"
        fi
else
        echo Is not number
fi

9、 Calculate the sum of any two integers entered by the user 、 Bad 、 The product of 、 merchant 、 remainder ,
Judge whether the parameters entered by the user are two , If not , Prompt usage ;
Judge whether the user input is an integer , If not , Give a prompt to terminate the operation .

#!/bin/bash
[ $# -ne 2 ] && {
    
 echo "usage: $0 num1 num2"
 exit 1
}
expr $1 + $2 + 10 &> /dev/null
if [ $? -ne 0 ]
then
 echo "you must input two number"
 exit 2
fi
echo "a+b=$(($1+$2))"
echo "a-b=$(($1-$2))"
echo "a*b=$(($1*$2))"
echo "a/b=$(($1/$2))"