vnstat

vnstat command shows bandwidth usage on your system.

[root@server12 ~]# vnstat
Database updated: Wed Dec 13 06:51:43 2017

   eth0 since 11/04/13

          rx:  4.81 TiB      tx:  63.40 TiB      total:  68.21 TiB

   monthly
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
       Nov '17     94.81 GiB |    2.02 TiB |    2.11 TiB |    7.00 Mbit/s
       Dec '17     54.05 GiB |    1.00 TiB |    1.05 TiB |    8.51 Mbit/s
     ------------------------+-------------+-------------+---------------
     estimated    136.37 GiB |    2.52 TiB |    2.65 TiB |

   daily
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
     yesterday      4.45 GiB |   84.15 GiB |   88.60 GiB |    8.60 Mbit/s
         today      1.36 GiB |   25.79 GiB |   27.15 GiB |    9.22 Mbit/s
     ------------------------+-------------+-------------+---------------
     estimated      4.77 GiB |   90.35 GiB |   95.11 GiB |
[root@server12 ~]# 

Bandwidth usage by day

[root@server12 ~]# vnstat -d

 eth0  /  daily

         day         rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
      11/14/17      3.11 GiB |   71.21 GiB |   74.32 GiB |    7.22 Mbit/s
      11/15/17      2.97 GiB |   68.86 GiB |   71.83 GiB |    6.97 Mbit/s
      11/16/17      3.14 GiB |   69.58 GiB |   72.72 GiB |    7.06 Mbit/s
      11/17/17      3.11 GiB |   72.84 GiB |   75.95 GiB |    7.37 Mbit/s
      11/18/17      2.87 GiB |   70.07 GiB |   72.94 GiB |    7.08 Mbit/s
      11/19/17      3.96 GiB |   64.32 GiB |   68.28 GiB |    6.63 Mbit/s
      11/20/17      2.71 GiB |   62.55 GiB |   65.26 GiB |    6.34 Mbit/s
      11/21/17      2.89 GiB |   66.82 GiB |   69.72 GiB |    6.77 Mbit/s
      11/22/17      2.86 GiB |   66.28 GiB |   69.14 GiB |    6.71 Mbit/s
      11/23/17      3.14 GiB |   72.26 GiB |   75.40 GiB |    7.32 Mbit/s
      11/24/17      3.26 GiB |   67.98 GiB |   71.24 GiB |    6.92 Mbit/s
      11/25/17      3.01 GiB |   66.87 GiB |   69.87 GiB |    6.78 Mbit/s
      11/26/17      3.70 GiB |   64.83 GiB |   68.53 GiB |    6.65 Mbit/s
      11/27/17      3.01 GiB |   68.27 GiB |   71.28 GiB |    6.92 Mbit/s
      11/28/17      2.88 GiB |   66.41 GiB |   69.29 GiB |    6.73 Mbit/s
      11/29/17      3.42 GiB |   73.41 GiB |   76.83 GiB |    7.46 Mbit/s
      11/30/17      2.94 GiB |   67.57 GiB |   70.52 GiB |    6.85 Mbit/s
      12/01/17      3.98 GiB |   73.32 GiB |   77.30 GiB |    7.51 Mbit/s
      12/02/17      3.86 GiB |   73.75 GiB |   77.61 GiB |    7.54 Mbit/s
      12/03/17      4.37 GiB |   79.14 GiB |   83.51 GiB |    8.11 Mbit/s
      12/04/17      3.64 GiB |   78.50 GiB |   82.14 GiB |    7.97 Mbit/s
      12/05/17      4.14 GiB |   80.11 GiB |   84.25 GiB |    8.18 Mbit/s
      12/06/17      4.61 GiB |   85.19 GiB |   89.80 GiB |    8.72 Mbit/s
      12/07/17      4.86 GiB |   85.86 GiB |   90.72 GiB |    8.81 Mbit/s
      12/08/17      4.56 GiB |   89.35 GiB |   93.91 GiB |    9.12 Mbit/s
      12/09/17      4.62 GiB |   88.69 GiB |   93.31 GiB |    9.06 Mbit/s
      12/10/17      5.11 GiB |   90.39 GiB |   95.50 GiB |    9.27 Mbit/s
      12/11/17      4.49 GiB |   88.47 GiB |   92.96 GiB |    9.03 Mbit/s
      12/12/17      4.45 GiB |   84.15 GiB |   88.60 GiB |    8.60 Mbit/s
      12/13/17      1.38 GiB |   26.12 GiB |   27.50 GiB |    9.23 Mbit/s
     ------------------------+-------------+-------------+---------------
     estimated      4.76 GiB |   90.43 GiB |   95.19 GiB |
[root@server12 ~]#