1惨远、顯示統(tǒng)計占用系統(tǒng)內(nèi)存最多的進(jìn)程，并排序孵奶。
## 按內(nèi)存使用排序
[root@localhost ~]# ps -eo pid,ppid,%cpu,%mem,args --sort=-%mem |head -10
PID PPID %CPU %MEM COMMAND
852 1 0.0 4.8 /usr/libexec/platform-python -s /usr/sbin/firewalld --nofork --nopid
849 824 0.0 4.7 /usr/libexec/sssd/sssd_nss --uid 0 --gid 0 --logger=files
877 1 0.0 3.8 /usr/libexec/platform-python -Es /usr/sbin/tuned -l -P
822 1 0.0 2.7 /usr/lib/polkit-1/polkitd --no-debug
867 1 0.0 2.4 /usr/sbin/NetworkManager --no-daemon
848 824 0.0 1.8 /usr/libexec/sssd/sssd_be --domain implicit_files --uid 0 --gid 0 --logger=files
824 1 0.0 1.7 /usr/sbin/sssd -i --logger=files
1 0 0.0 1.6 /usr/lib/systemd/systemd --switched-root --system --deserialize 17
3116 878 0.0 1.3 sshd: root [priv]
[root@localhost ~]#
#按cpu 利用率排序
[root@localhost ~]# ps -eo pid,ppid,%cpu,%mem,args --sort=-%cpu |head -10
PID PPID %CPU %MEM COMMAND
2935 2 0.1 0.0 [kworker/1:2-events_power_efficient]
1 0 0.0 1.6 /usr/lib/systemd/systemd --switched-root --system --deserialize 17
2 0 0.0 0.0 [kthreadd]
3 2 0.0 0.0 [rcu_gp]
4 2 0.0 0.0 [rcu_par_gp]
6 2 0.0 0.0 [kworker/0:0H-kblockd]
8 2 0.0 0.0 [mm_percpu_wq]
9 2 0.0 0.0 [ksoftirqd/0]
10 2 0.0 0.0 [rcu_sched]
2疲酌、編寫腳本，使用for和while分別實現(xiàn)192.168.0.0/24網(wǎng)段內(nèi)拒课，地址是否能夠ping通徐勃，若ping通則輸出"success!"，若ping不通則輸出"fail!"
### 使用for
[root@localhost shell]# cat ping_for.sh
#!/bin/bash
IP="192.168.0."
for ip in {2..254}
do
{
if `ping -c 3 $IP$ip > /dev/null`; then
echo "ping $IP$ip is success!!! "
else
echo "ping $IP$ip is fail!!!"
fi
}&
done
wait
[root@localhost shell]#
[root@localhost shell]# ./ping_for.sh
ping 192.168.0.100 is success!!!
ping 192.168.0.103 is success!!!
ping 192.168.0.101 is success!!!
ping 192.168.0.2 is fail!!!
ping 192.168.0.4 is fail!!!
ping 192.168.0.7 is fail!!!
ping 192.168.0.8 is fail!!!
### 使用while
[root@localhost shell]# cat ping_while.sh
#!/bin/bash
IP="192.168.0."
declare -i ip=1
while [[ $ip -lt 255 ]]
do
{
if `ping -c 3 $IP$ip > /dev/null`; then
echo "ping $IP$ip is success!!!"
else
echo "ping $IP$ip is fail!!!"
fi
}&
let ip++
done
wait
[root@localhost shell]#
[root@localhost shell]# ./ping_while.sh
ping 192.168.0.1 is success!!!
ping 192.168.0.100 is success!!!
ping 192.168.0.101 is success!!!
ping 192.168.0.103 is success!!!
ping 192.168.0.104 is success!!!
ping 192.168.0.102 is success!!!
ping 192.168.0.3 is fail!!!
ping 192.168.0.8 is fail!!!
ping 192.168.0.5 is fail!!!
ping 192.168.0.9 is fail!!!
ping 192.168.0.13 is fail!!!
3早像、每周的工作日1:30僻肖，將/etc備份至/backup目錄中，保存的文件名稱格式 為“etcbak-yyyy-mm-dd-HH.tar.xz”卢鹦，其中日期是前一天的時間
[root@localhost shell]# ./etc_backup.sh
backuping file etcbak-2021-02-20-09.tar.xz
backup successed !!!
[root@localhost shell]# tree /opt/
/opt/
└── backup
└── etcbak-2021-02-20-09.tar.xz
1 directory, 1 file
[root@localhost shell]# date
Sun Feb 21 09:02:37 EST 2021
[root@localhost shell]#
[root@localhost shell]# cat etc_backup.sh
#!/bin/bash
filename="etcbak-`date -d '- 1 day' +%F-%H`.tar.xz"
echo "backuping file $filename"
backup_path="/opt/backup"
[ -d $backup_path ]
if [ $? -ne 0 ]; then
mkdir -p $backup_path
fi
cd $backup_path
`/usr/bin/tar czpPf $filename /etc/* &> /dev/null`
[ -f $filename ]
if [ $? -eq 0 ]; then
echo "backup successed !!!"
else
echo "backup action failed !!! please check"
fi
[root@localhost shell]#
[root@localhost ~]# crontab -l
## backup etc
30 1 * * 0 /bin/bash /root/shell/etc_backup.sh
[root@localhost ~]#
4臀脏、工作日時間，每10分鐘執(zhí)行一次磁盤空間檢查冀自，一旦發(fā)現(xiàn)任何分區(qū)利用率高 于80%揉稚，就發(fā)送郵件報警。
[root@localhost shell]# cat check_disk.sh
#!/bin/bash
Disk=`df -TPh|awk '+$6>10 {print $1}'|tail -1`
if [[ -n $Disk ]];then
echo "The part : $DISK will be full,please check !" | mail -s 'DISK WARNNING' root
fi
[root@localhost shell]#
[root@localhost shell]# ./check_disk.sh
[root@localhost shell]# mail
Heirloom Mail version 12.5 7/5/10. Type ? for help.
"/var/spool/mail/root": 8 messages 1 new 2 unread
1 root Sun Feb 21 09:38 22/892 "DISK WARNNING"
2 root Sun Feb 21 09:38 22/892 "DISK WARNNING"
3 root Sun Feb 21 09:38 22/892 "DISK WARNNING"
4 root Sun Feb 21 09:38 22/892 "DISK WARNNING"
5 root Sun Feb 21 09:38 22/892 "DISK WARNNING"
6 root Sun Feb 21 09:38 22/902 "DISK WARNNING"
U 7 root Sun Feb 21 09:38 22/901 "DISK WARNNING"
>N 8 root Sun Feb 21 09:39 21/881 "DISK WARNNING"
&
Message 8:
From root@localhost.localdomain Sun Feb 21 09:39:13 2021
Return-Path: <root@localhost.localdomain>
From: root <root@localhost.localdomain>
Date: Sun, 21 Feb 2021 09:39:13 -0500
To: root@localhost.localdomain
Subject: DISK WARNNING
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
Status: R
The part : will be full,please check !
&
