1、顯示統(tǒng)計(jì)占用系統(tǒng)內(nèi)存最多的進(jìn)程，并排序。
[19:08:53 root@centos7 ~]#ps -eo pid,ppid,cmd,%mem --sort=-%mem | head
PID PPID CMD %MEM
1337 1294 /usr/bin/gnome-shell 7.0
1277 1016 /usr/bin/X :0 -background n 1.6
1004 1 /usr/bin/python2 -Es /usr/s 1.0
1011 1 /usr/sbin/libvirtd 0.9
1445 1294 /usr/libexec/gsd-media-keys 0.8
1486 1294 /usr/libexec/gsd-wacom 0.7
1424 1294 /usr/libexec/gsd-xsettings 0.7
1455 1294 /usr/libexec/gsd-power 0.7
1433 1294 /usr/libexec/gsd-color 0.7
2、編寫腳本，使用for和while分別實(shí)現(xiàn)192.168.0.0/24網(wǎng)段內(nèi)，地址是否能夠ping通，若ping通則輸出"success!"，若ping不通則輸出"fail!"
1)for循環(huán)腳本
for((i=1;i<=254;i++));do
for((j=1;j<=254;j++));do
ping -c 1 -w 1 192.168.$i.$j &>/dev/null && echo "ping 192.168.$i.$j is success!" || echo ping "192.168.$i.$j is fail!"
done
done
執(zhí)行結(jié)果
[19:41:51 root@centos7 scripts]#bash ping.sh
ping 192.168.1.1 is success!
ping 192.168.1.2 is fail!
ping 192.168.1.3 is fail!
ping 192.168.1.4 is fail!
ping 192.168.1.5 is fail!
ping 192.168.1.6 is fail!
ping 192.168.1.7 is fail!
ping 192.168.1.8 is fail!
ping 192.168.1.9 is fail!
ping 192.168.1.10 is fail!
ping 192.168.1.11 is fail!
ping 192.168.1.12 is fail!
ping 192.168.1.13 is fail!
ping 192.168.1.14 is fail!
ping 192.168.1.15 is fail!
......
2)while循環(huán)腳本
i=1
j=1
while ((i<=254));do
while ((j<=254));do
ping -c 1 -w 1 192.168.$i.$j &>/dev/null && echo "ping 192.168.$i.$j is success!" || echo ping "192.168.$i.$j is fail!"
let j++
done
let i++
done
執(zhí)行結(jié)果
[20:07:26 root@centos7 scripts]#bash while_ping.sh
ping 192.168.1.1 is success!
ping 192.168.1.2 is fail!
ping 192.168.1.3 is fail!
ping 192.168.1.4 is fail!
ping 192.168.1.5 is fail!
ping 192.168.1.6 is fail!
ping 192.168.1.7 is fail!
ping 192.168.1.8 is fail!
ping 192.168.1.9 is fail!
3、每周的工作日1:30，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”，其中日期是前一天的時(shí)間
[20:24:23 root@centos7 ~]#crontab -e
no crontab for root - using an empty one
30 1 * * 1-5 /usr/bin/tar -Jcf /backup/etcbak-`/usr/bin/date -d yesterday +%F-%H`.tar.xz /etc &>/dev/null
4、工作日時(shí)間，每10分鐘執(zhí)行一次磁盤空間檢查，一旦發(fā)現(xiàn)任何分區(qū)利用率高 于80%，就發(fā)送郵件報(bào)警
先編寫磁盤容量檢查腳本，腳本如下：
for DISK in `df | awk -F " +|%" '/\/dev\/sd/{print $5}'`;do
if [[ $DISK -gt 80 ]];then
mail -s "Disk capacity alarm" root@localhost < /data/disk_alarm.txt
fi
done
將該腳本執(zhí)行設(shè)置為定時(shí)任務(wù)
[21:30:21 root@centos7 data]#crontab -e
*/10 * * * 1-5 /usr/bin/bash /data/diskcheck.sh
