1.How to check the NIC traffic in real time? How to view historical NIC traffic?
yum install -y sysstat# install sysstat package, get sar command
sar -n DEV# view NIC traffic, default 10 minutes update
sar -n DEV 1 10# is displayed once in a second, showing a total of 10 times
sar -n DEV -f /var/log/sa/sa22 #View the traffic log for the specified date
sar -q -f -f /var/log/sa/sa22
2.Show running process
$ps -aux
Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.8/FAQ
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 2900 1428 ? Ss 10:43 0:01 /sbin/init
root 2 0.0 0.0 0 0 ? S 10:43 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? S 10:43 0:00 [migration/0]
root 4 0.0 0.0 0 0 ? S 10:43 0:00 [ksoftirqd/0]
#STAT: S = sleeping , s = main process, Z =zombie process
$ps -elf
F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD
4 S root 1 0 0 80 0 - 725 - 10:43 ? 00:00:01 /sbin/init
1 S root 2 0 0 80 0 - 0 - 10:43 ? 00:00:00 [kthreadd]
1 S root 3 2 0 -40 - - 0 - 10:43 ? 00:00:00 [migration/0]
1 S root 4 2 0 80 0 - 0 - 10:43 ? 00:00:00 [ksoftirqd/0]
1 S root 5 2 0 -40 - - 0 - 10:43 ? 00:00:00 [migration/0]
vim /etc/sysconfig/network-scripts/ifcft-eth0
#restart NIC
ifdown eth0
ifup eth0
#or restart network service
service network restart
6. Set multiple IP in one NIC
#ip1
cat /etc/sysconfig/network-scripts/ifcfg-eth0
#ip2
cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0:1
vim /etc/sysconfig/network-scripts/ifcfg-eth0:1
#restart
service network restart
7.How do I check if a NIC is connected to a switch?
mii-tool eth0
#or
ethtool eth0
8.NAT
NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.
9.Transfer files larger than 10K in the current directory to the /tmp directory.
#/bin/sh
#Programm :
# Using for move currently directory to /tmp
for FileName in `ls -l |awk ‘$5>10240 {print $9}’`
do
mv $FileName /tmp
done
ls -la /tmp
echo “Done! ”
