Here are some nice tools in the Ubuntu repositories for command line network traffic monitoring:

bmon - shows multiple interfaces at once

slurm - has nice colored graphs

tcptrack - A favorite. Tells how much bandwidth is being used and also what protocol (service/port) and destination the transmission is taking place to. Very helpful when you want to know exactly what is using up your bandwidth

It's quite easy! install "iftop" with:

sudo apt-get install iftop

Then run

sudo iftop

from any terminal!

Enjoy!

Someone should also have mentioned nethogs.

sudo apt-get -y install nethogs
sudo nethogs

The thing that's different and maybe is cooler about this one is that it shows traffic per process, like the image shows

Take a look at the page

There is a nice tool called speedometer that displays a graph in the terminal using Unicode block characters, colors, and even adds labels to each peak in the graph.

$ sudo apt-get install speedometer
$ speedometer -l  -r wlan0 -t wlan0 -m $(( 1024 * 1024 * 3 / 2 ))

It has several options, can monitor multiple interfaces, can show multiple graphs in several rows or columns, and can even monitor the download speed of a single file (by watching the file size on disk).

iptraf

IPTraf is a console-based network statistics utility for Linux. It gathers a variety of figures such as TCP connection packet and byte counts, interface statistics and activity indicators, TCP/UDP traffic breakdowns, and LAN station packet and byte counts.

Features

An IP traffic monitor that shows information on the IP traffic passing over your network. Includes TCP flag information, packet and byte counts, ICMP details, OSPF packet types. General and detailed interface statistics showing IP, TCP, UDP, ICMP, non-IP and other IP packet counts, IP checksum errors, interface activity, packet size counts. A TCP and UDP service monitor showing counts of incoming and outgoing packets for common TCP and UDP application ports A LAN statistics module that discovers active hosts and shows statistics showing the data activity on them TCP, UDP, and other protocol display filters, allowing you to view only traffic you're interested in. Logging Supports Ethernet, FDDI, ISDN, SLIP, PPP, and loopback interface types. Utilizes the built-in raw socket interface of the Linux kernel, allowing it to be used over a wide range of supported network cards. Full-screen, menu-driven operation.

Protocols Recognized

IP TCP UDP ICMP IGMP IGP IGRP OSPF ARP RARP

Non-IP packets will simply be indicated as "Non-IP" and, on Ethernet LAN's, will be supplied with the appropriate Ethernet addresses.

Supported Interfaces

Local loopback All Linux-supported Ethernet interfaces All Linux-supported FDDI interfaces SLIP Asynchronous PPP Synchronous PPP over ISDN ISDN with Raw IP encapsulation ISDN with Cisco HDLC encapsulation Parallel Line IP

Source http://iptraf.seul.org/about.html

Installation

With apt:

apt-get install iptraf

Or download the source:

http://iptraf.seul.org/download.html

Screenshots

Current Connections:

Current Ports:

Summary of all Interfaces:

Detailed per Interface:

Source http://iptraf.seul.org/shots.html

tcpdump -i eth0 

That will give you a streaming information of all the data flowing from that interface (your ethernet card). Similar to wireshark.

Use ifconfig to see a list of your machines interfaces.

I think ifconfig [interface] will do that. Like:

gevorg@gevorg-TravelMate-3260:~$ ifconfig wlan0
wlan0     Link encap:Ethernet  HWaddr 00:18:de:89:52:71  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

gevorg@gevorg-TravelMate-3260:~$ ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:16:36:bf:92:e3  
          inet addr:192.168.10.100  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::216:36ff:febf:92e3/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:342765 errors:0 dropped:0 overruns:0 frame:0
          TX packets:306183 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:373934806 (373.9 MB)  TX bytes:39111569 (39.1 MB)
          Interrupt:16 

It shows RX bytes:73934806 (373.9 MB) and TX bytes:39111569 (39.1 MB).

If you are looking for something extremely simple, but still useful, try ifstat

$ sudo apt-get install ifstat
$ ifstat
       eth0               wlan0       
 KB/s in  KB/s out   KB/s in  KB/s out
    0.00      0.00      0.96      4.79
    0.00      0.00      0.04      0.14

It monitors all interfaces at once, printing a new line every second. Useful to pipe into another script, or to leave running and observe the bandwidth usage over time. Not as pretty as other tools, but it gets the job done.

There are some useful options listed in the manpage:

-z  Hides interface which counters are null, eg interfaces that are up but not used.
-n  Turns off displaying the header periodically.
-t  Adds a timestamp at the beginning of each line.
-T  Reports total bandwith for all monitored interfaces.
-S  Keep stats updated on the same line if possible (no scrolling nor wrapping).
-b  Reports bandwith in kbits/sec instead of kbytes/sec.

This is not specific to networking, but Glances can display network traffic of different interfaces.

Install it with one of those commands :

sudo snap install glances
sudo apt install glances

Another useful tool is sar. Install it,

apt install sysstat

How to use it:

sar -n DEV  1

And Brendan's amazing graph guide:

References

• http://www.brendangregg.com/linuxperf.html
• Linux Performance Observability: sar