一：编写脚本，判断当前系统剩余内存大小，如果低于100M，邮件报警管理员，使用计划任务，每10分钟检查一次

[root@shell test]# vim free_mem.sh
#!/bin/bash
free_mem=$(free -m  | grep "Mem:" | tr -s " " | cut -d " " -f4)
if [ "$free_mem" -le 100 ];thenecho "剩余内存：${free_mem},不足100M " | mail -s "内存不足" root@shell
fi
[root@shell test]# chmod a+rx free_mem.sh
[root@shell test]# crontab -e 
*/10 * * * * /test/free_mem.sh &> /dev/null

二：判断 sshd 进程是否运行，如果服务启动打印启动，未启动则打印未启动（使用查看进程和端口两种方式）

[root@shell test]# vim sshd.sh
#!/bin/bashnu=$( ps -ef | grep sshd | grep -v grep | wc -l)
if [ $nu -ge 1 ]
thenecho "sshd is running"
elseecho "sshd is not running"systemctl start sshd > /dev/null
fi
[root@shell test]# chmod a+xr sshd.sh 
[root@shell test]# bash sshd.sh 
sshd is running

三：检查主机是否存活，并输出结果(使用for循环实现：主机数>=2)

[root@shell test]# vim ping.sh
#!/bin/bash
#########################
#File name:ping.sh
#Version:v1.0
#Email:admin@test.com
#Created time:2022-08-22 20:03:32
#Description:
#########################
ping -c 2 -w 1 192.168.10.1 &> /dev/null
if [ $? -eq 0 ]
thenecho host is running 
elseecho host is not running
fi
[root@shell test]# chmod a+rx ping.sh
[root@shell test]# bash ping.sh 
host is not running

四：根据用户输入成绩，判断优良中差(A,B,C,D, 注意边界问题)

#########################
#File name:score.sh
#Version:v1.0
#Email:admin@test.com
#Created time:2022-08-22 20:38:15
#Description:
#########################
read -p "please input your score:" score if [ -z "$score" ];then  echo "you must input your score"  exit 1fiif [ "$score" -lt 0 -o "$score" -gt 100 ];then  echo "score invalid"exit 2i
fi
if [ "$score" -ge 85 ];then echo "A"  elif [ "$score" -ge 70 ];then
echo "B"elif [ "$score" -ge 60 ];then
echo "C"else echo "D" 
fi
[root@shell test]# vim score.sh
[root@shell test]# chmod a+rx score.sh 
[root@shell test]# ./score.sh 
please input your score:33
D

五：判断当前主机的CPU生产商，其信息在/proc/cpuinfo文件中vendor_id一行中

[root@shell test]# vim vendor.sh
#!/bin/bash
#########################
#File name:vendor.sh
#Version:v1.0
#Email:admin@test.com
#Created time:2022-08-22 22:49:37
#Description:
#########################
vendor=$(grep "vendor_id" /proc/cpuinfo |uniq|awk -F: '{print $NF}') if [[ "$vendor" =~ [[:space:]]*GenuineIntel$ ]]  
thenecho "intel" elif [[ "$vendor" =~ [[:space:]]*AuthenticAMD$ ]] then
echo "AMD" elseecho "unknow" 
fi
[root@shell test]# chmod a+rx vendor.sh 
[root@shell test]# ./vendor.sh 
intel