Linux shell script Real-time monitor network card traffic

Through the/proc/net/dev can be viewed to the network card traffic, according to the changes in the value of the file in conjunction with while loop write a real-time monitoring network card script, by specifying the network card name as parameters to monitor the traffic of the specified network card

#!/bin/bash
While ["1"]
Todo
Eth=$1
rxpre=$ (Cat/proc/net/dev | grep $eth | tr: "" | awk ' {print $} ')
txpre=$ (Cat/proc/net/dev | grep $eth | tr: "" | awk ' {print $} ')
Sleep 1
rxnext=$ (Cat/proc/net/dev | grep $eth | tr: "" | awk ' {print $} ')
txnext=$ (Cat/proc/net/dev | grep $eth | tr: "" | awk ' {print $} ')
Clear
Echo-e "T RX ' date +%k:%m:%s ' TX"
rx=$ ((${rxnext}-${rxpre}))
tx=$ ((${txnext}-${txpre}))
if [[$RX-lt 1024]];then
rx= "${RX}B/S"
elif [[$RX-gt 1048576]];then
rx=$ (echo $RX | awk ' {print $1/1048576 ' MB/S "} ')
Else
rx=$ (echo $RX | awk ' {print $1/1024 ' kb/s '} ')
Fi
if [[$TX-lt 1024]];then
tx= "${TX}B/S"
elif [[$TX-gt 1048576]];then
tx=$ (echo $TX | awk ' {print $1/1048576 ' MB/S "} ')
Else
tx=$ (echo $TX | awk ' {print $1/1024 ' kb/s '} ')
Fi
Echo-e "$eth t $RX $TX"
Done

Example 2, awk implementation of real-time monitoring network card traffic script (Common Application II)

Implementation principle:

[Chengmo@localhost ~]$ Cat/proc/net/dev
inter-|  Receive | Transmit
Face |bytes packets errs drop FIFO frame compressed multicast|bytes packets errs Drop FIFO colls carrier compressed
lo:1068205690 1288942839 0 0 0 0 0 0 1068205690 1288942839 0 0 0 0-0 0
eth0:91581844 334143895 0 0 0 0 0 145541676 4205113078 3435231517 0 0 0 0-0 0

The Proc/net/dev file saves the total traffic information of the NIC, and adds the network card to the record through interval interval. The actual rate is obtained before subtracting.

Program code:

awk ' begin{
Ofmt= "%.3f";
Devf= "/proc/net/dev";
while (("Cat" DEVF) | Getline)
{
if ($ ~/:/&& ($10+0) > 0)
{
Split ($1,tarr, ":");
NET[TARR[1]]=$10+TARR[2];
Print tarr[1],$10+tarr[2];
}
}
Close (DEVF);
while (System (' Sleep 1 ') >=0)
{
System ("clear");
while (Getline < DEVF)
{
if ($ ~/:/&& ($10+0) > 0)
{
Split ($1,tarr, ":");
if (tarr[1] in net)
{
Print tarr[1], ":", ($10+tarr[2]-net[tarr[1]]) *8/1024, "kb/s";
NET[TARR[1]]=$10+TARR[2];
}
}
}
Close (DEVF);
}
}'

Description: The first while is to obtain the total initial value, is the network card out of traffic, $ is the network card into traffic. The 2nd while will be started one time interval of 1 seconds. Calculating the total flow difference gets the average flow per second.

Note: Close is required to read the file line by Getline. Otherwise, the data cannot be obtained in the 2nd while loop.

Example 3

Network Card monitoring footsteps:

A script command to monitor the real-time traffic of the network card.

Script code content:

#!/bin/bash
If [-Z "$"]; Then
Echo
echo Usage: $ network-interface
Echo
echo e.g. $ eth0
Echo
Exit
Fi
If=$1
While True
Todo
r1= ' Cat/sys/class/net/$1/statistics/rx_bytes '
t1= ' Cat/sys/class/net/$1/statistics/tx_bytes '
Sleep 1
R2= ' Cat/sys/class/net/$1/statistics/rx_bytes '
T2= ' Cat/sys/class/net/$1/statistics/tx_bytes '
tbps= ' Expr $T 2-$T 1 '
rbps= ' Expr $R 2-$R 1 '
tkbps= ' expr $TBPS/1024 '
rkbps= ' expr $RBPS/1024 '
Echo "TX $: $TKBPS kb/s Rx $: $RKBPS kb/s"
Done

Footstep Use Method:

1. In order for the script file to be convenient to use, it is placed in the/sbin directory.

#cd/sbin
#vim Netspeed
Enter Footstep content to save exit.

#chmod +x Netspeed

2. Use Footsteps command:

#netspeed eth0

(This is based on the host network card information input adapter name, if not clear network card information, you can use the Ifconfig command to view)