[root@centos7 ~]# ps -eo uid,pid,ppid,tty,c,time,cmd,%mem --sort=-%mem
UID PID PPID TT C TIME CMD %MEM
? :: /usr/bin/gnome-shell 12.9
tty1 :: /usr/bin/X : -background n 2.3
? :: /usr/libexec/gsd-media-keys 1.7
? :: /usr/bin/python2 -Es /usr/s 1.7
? :: /usr/lib/polkit-/polkitd - 1.4
? :: /usr/sbin/libvirtd 1.4
? :: /usr/libexec/gsd-xsettings 1.4
? :: /usr/libexec/gsd-power 1.4
? :: /usr/libexec/gsd-color 1.4
…以下省略

　1. for 循环实现

#!/bin/bash

NETID=192.168.
for HOSTID in {..};do
{
ping -c1 -W1 $NETID.$HOSTID &> /dev/null
if [ $? -eq ];then
echo "$NETID.$HOSTID success!"
else
echo "$NETID.$HOSTID fail!"
fi
} &
done

　2. while 循环实现

#!/bin/bash

NETID=192.168.
declare -i HOSTID=

while [ $HOSTID -lt ];do

ping -c1 -W1 $NETID.$HOSTID &> /dev/null

if [ $? -eq ];then
echo "$NETID.$HOSTID success!"
else
echo "$NETID.$HOSTID fail!"
fi

let HOSTID++

done

[root@centos7 ~]# crontab -e
* * - /usr/bin/tar -Jcf etcbak-`date -d "-1 day" +%Y-%m-%d-%H`.tar.xz /etc &> /dev/null

　1. 先准备报警脚本

[root@centos7 data]# vim while_checkdisk.sh
#!/bin/bash

WARNING=
MAIL=root@localhost

df |sed -rn '/^\/dev\/sd/s#^([^[:space:]]+).* ([[:digit:]]+)%.*#\1 \2#p'|while read diskpart used;do

if [ $used -gt $WARNING ];then
echo $diskpart will be full,used:$used% | mail -s "diskcheck_alert" $MAIL
fi
done

　2. 给脚本加执行权限

[root@centos7 data]# chmod +x while_checkdisk.sh

　3. 添加定时任务

[root@centos7 data]# crontab -e
*/ * * * * /bin/bash /data/while_checkdisk.sh &> /dev/null