1、显示统计占用系统内存最多的进程，并排序。
[root@localhost ~]# ps aux --sort=-%mem
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 711 0.0 1.4 357972 28972 ? Ssl 04:46 0:00 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
root 1053 0.0 0.9 695044 19208 ? Ssl 04:46 0:00 /usr/sbin/libvirtd
root 1047 0.0 0.9 573820 19200 ? Ssl 04:46 0:00 /usr/bin/python -Es /usr/sbin/tuned -l -P
polkitd 635 0.0 0.7 542312 15160 ? Ssl 04:46 0:00 /usr/lib/polkit-1/polkitd --no-debug
root 723 0.0 0.4 570160 10136 ? Ssl 04:46 0:00 /usr/sbin/NetworkManager --no-daemon
root 390 0.0 0.4 200988 8156 ? Ss 04:46 0:00 /usr/sbin/lvmetad -f
root 1 0.2 0.3 193688 6772 ? Ss 04:46 0:02 /usr/lib/systemd/systemd --switched-root --system --deserialize 22
2、编写脚本，使用for和while分别实现192.168.0.0/24网段内，地址是否能够ping通，若ping通则输出"success!"，若ping不通则输出"fail!"
# for循环
[root@localhost data]# cat ping_demo.sh
#!/bin/bash
for i in `seq 255`
do
ip=192.168.80.${i}
ping -c1 $ip >& /dev/null
if [ ! $? -eq 0 ];
then
echo "$ip is failed!!!"
else
echo "$ip is sucess!"
fi
done
#while循环
[root@localhost data]# cat ping_while.sh
#!/bin/bash
count=255
i=1
while [ $i -le $count ];
do
ip=192.168.80.${i}
ping -c1 $ip &> /dev/null
if [ $? -eq 0 ];
then
echo "$ip is sucess!"
else
echo "$ip is failed!"
fi
let i++
done
3、每周的工作日1:30，将/etc备份至/backup目录中，保存的文件名称格式 为“etcbak-yyyy-mm-dd-HH.tar.xz”，其中日期是前一天的时间
### 先编写备份脚本
[root@localhost data]# cat backup_etc.sh
#!/bin/bash
back_dir='/etc'
dest_dir='/root/'
back_date=`date -d "1 day ago" +"%Y-%m-%d-%H"`
back_name='etcbak-'$back_date
tar -cpJ $back_dir -f ${back_name}.tar.xz &>/dev/null
mv ./${back_name}.tar.xz $dest_dir
### 再将脚本放入计划任务中执行
[root@localhost data]# cat /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
# For details see man 4 crontabs
# Example of job definition:
# .---------------- minute (0 - 59)
# | .------------- hour (0 - 23)
# | | .---------- day of month (1 - 31)
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ...
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# | | | | |
# * * * * * user-name command to be executed
30 1 * * 1-5 root /data/backup_etc.sh
4、工作日时间，每10分钟执行一次磁盘空间检查，一旦发现任何分区利用率高 于80%，就发送邮件报警
### 先编写备份脚本
[root@localhost data]# cat monitor_disk.sh
#!/bin/bash
df -h |awk '/^\/dev/ {print $1,int($5)}' > /root/tmp_disk.txt
while read i ;
do
PART=$(echo $i |cut -d" " -f1)
USE=$(echo $i |cut -d" " -f2)
if [ $USE -gt 20 ]; then
echo "
part: $PART
use: $USE
" | mail -s "monitor part used " root
fi
done < /root/tmp_disk.txt
### 脚本单独测试结果
[root@localhost data]# mail
Heirloom Mail version 12.5 7/5/10. Type ? for help.
"/var/spool/mail/root": 2 messages 1 new
1 root Tue Feb 18 06:18 22/650 "monitor part used"
>N 2 root Tue Feb 18 06:30 21/646 "monitor part used"
& 2
Message 2:
From root@localhost.localdomain Tue Feb 18 06:30:13 2020
Return-Path: <root@localhost.localdomain>
X-Original-To: root
Delivered-To: root@localhost.localdomain
Date: Tue, 18 Feb 2020 06:30:13 +0800
To: root@localhost.localdomain
Subject: monitor part used
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
From: root@localhost.localdomain (root)
Status: R
part: /dev/sda1
use: 30
###再将备份脚本放入计划任务执行
30 1 * * 1-5 root /data/back_etc.sh
*/10 * * * 1-5 root /data/monitor_disk.sh
