Network Monitor Tool

#!/usr/bin/env bash

# - iNFO --------------------------------------
#
#   Author: wuseman <wuseman@nr1.nu>
# FileName: wbw.sh
#  Created: 2023-07-27 (19:47:47)
# Modified: 2026-03-18 (05:51:32)
#  Version: 1.0
#  License: WFTPL
#
#      iRC: wuseman (Libera/EFnet/LinkNet)
#   GitHub: https://github.com/wuseman/
#
# ---------------------------------------------


function show_header() {
    local i_w=16 d_w=16 dm_w=16 u_w=15 um_w=15
    # ASCII Separator
    divider=$(printf "+ %-${i_w}s + %-${d_w}s + %-${dm_w}s + %-${u_w}s + %-${um_w}s +\n" " " " " " " " " " ")
    divider="${divider// /-}"
    
    # ASCII Footer
    footer=$(printf "|_%-${i_w}s_|_%-${d_w}s_|_%-${dm_w}s_|_%-${u_w}s_|_%-${um_w}s_|\n" " " " " " " " " " ")
    footer="${footer// /_}"

    echo "$divider"
    printf "| %-16s | %-16s | %-16s | %-15s | %-15s |\n" "Interface" "Download" "Download Max" "Upload" "Upload Max"
    echo "$divider"
}

function get_bytes() {
    local iface=$1
    read -r _ rec _ _ _ _ _ _ _ trans _ < <(grep "$iface:" /proc/net/dev)
    received_bytes=${rec#*:}
    transmitted_bytes=$trans
}

function get_velocity() {
    local value=$1 old_value=$2 time_diff=$3
    if (($(bc <<< "$time_diff < 0.1"))); then
        printf "0.00 MB/s"
        return
    fi
    local vel=$(bc <<< "scale=2; ($value - $old_value) / 1048576 / $time_diff")
    printf "%.2f MB/s" "$vel"
}

function get_max() {
    local new_raw=$(echo "$1" | grep -oP "\d*\.?\d+")
    local old_raw=$(echo "$2" | grep -oP "\d*\.?\d+")
    [[ -z "$old_raw" ]] && old_raw="0.00"
    if (($(bc -l <<< "$new_raw > $old_raw"))); then
        printf "%.2f MB/s" "$new_raw"
    else
        printf "%.2f MB/s" "$old_raw"
    fi
}

interfaces=()
while getopts ":i:a" opt; do
    case $opt in
        i) interfaces+=("$OPTARG") ;;
        a) while read -r l; do
               iface=$(echo "$l" | cut -d: -f1 | xargs)
               [[ -n "$iface" ]] && interfaces+=("$iface")
           done < <(tail -n +3 /proc/net/dev) ;;
    esac
done

[[ ${#interfaces[@]} -eq 0 ]] && exit 1

declare -A old_recv_map old_trans_map max_dl_map max_ul_map

for iface in "${interfaces[@]}"; do
    get_bytes "$iface"
    old_recv_map[$iface]=$received_bytes
    old_trans_map[$iface]=$transmitted_bytes
    max_dl_map[$iface]="0.00 MB/s"
    max_ul_map[$iface]="0.00 MB/s"
done

show_header
last_time=$(date +%s.%N)
first_run=1

tput civis
trap 'tput cnorm; echo; exit' INT TERM

while true; do
    current_time=$(date +%s.%N)
    delta_t=$(bc <<< "$current_time - $last_time")
    last_time=$current_time

    # If not first run, move up: Interface lines + 1 (footer)
    if [[ $first_run -eq 0 ]]; then
        tput cuu $((${#interfaces[@]} + 1))
    fi

    for iface in "${interfaces[@]}"; do
        get_bytes "$iface"
        v_rec=$(get_velocity "$received_bytes" "${old_recv_map[$iface]}" "$delta_t")
        v_tra=$(get_velocity "$transmitted_bytes" "${old_trans_map[$iface]}" "$delta_t")
        m_dl=$(get_max "$v_rec" "${max_dl_map[$iface]}")
        m_ul=$(get_max "$v_tra" "${max_ul_map[$iface]}")

        # Clear line and print data
        printf "\r\033[K| \e[1m%-16s\e[0m | \e[1;31m↓\e[0m %-14s | \e[1;34m%-16s\e[0m | \e[1;32m↑\e[0m %-13s | \e[1;34m%-15s\e[0m |\n" \
            "$iface" "$v_rec" "$m_dl" "$v_tra" "$m_ul"

        old_recv_map[$iface]=$received_bytes
        old_trans_map[$iface]=$transmitted_bytes
        max_dl_map[$iface]=$m_dl
        max_ul_map[$iface]=$m_ul
    done

    # Print footer with a newline and clear trailing artifacts
    printf "\r\033[K%s\n" "$footer"
    
    first_run=0
    sleep 1
done