Monitor network traffic volume over interface

Solution 1:

The data you want to see shows up in good old ifconfig.

watch ifconfig eth0

or to make things stand out better:

watch -n 1 -d ifconfig eth0

Solution 2:

I use iftop command. It shows statistics in realtime.

iftop -i eth0

Checkout some sceenshots here:

http://www.thegeekstuff.com/2008/12/iftop-guide-display-network-interface-bandwidth-usage-on-linux/

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Solution 3:

Without installing new tools:

while ifconfig eth0 | grep 'RX bytes'; do sleep 10; done

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Solution 4:

on post-2015 or so linux this might be better watch -n1 -d ip -s link show [interface]

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Solution 5:

function humanValue()
{
    h=( '' K M G T P )
    i=1; v=$(( $1 * 8 ))
    while [ $v -gt $(( 1 << 10 * i )) ]; do let i++; done;
    echo -n "$(( $v >> 10 * --i )) ${h[i]}b/s";
}
ifaces=$(ip addr | grep -E "^[0-9]:" | cut -d" " -f2 | tr -d \:)
declare -A RX2 TX2;
while sleep 1; 
do
    date 
    for INTERFACE in $ifaces;
    do
        RX1=$(cat /sys/class/net/${INTERFACE}/statistics/rx_bytes)
        TX1=$(cat /sys/class/net/${INTERFACE}/statistics/tx_bytes)
        DOWN=$(( RX1 - RX2[$INTERFACE] ))
        UP=$(( TX1 - TX2[$INTERFACE] ))
        RX2[$INTERFACE]=$RX1; TX2[$INTERFACE]=$TX1
        echo -e "[ $INTERFACE:\tRX: $(humanValue $DOWN)\t|\tTX: $(humanValue $UP) ]"
    done;
done;