pcrockett · February 8, 2021 18:24
diff --git a/pinger.sh b/pinger.sh
 #!/usr/bin/env bash

 # LICENSE: GPLv3 - https://www.gnu.org/licenses/gpl-3.0.en.html

 set -Eeuo pipefail

 [[ "${BASH_VERSINFO[0]}" -lt 5 ]] && echo "Bash >= 5 required" && exit 1

 readonly DEPENDENCIES=(ping)
 readonly SCRIPT_NAME=$(basename "${0}")

 function show_usage() {
    printf "Usage: %s [OPTIONS...] [TARGET]\n" "${SCRIPT_NAME}" >&2
    printf "  -t, --ttl\t\t\tSet ping TTL\n" >&2
    printf "  -h, --help\t\t\tShow this help message then exit\n" >&2
 }

 function panic() {
    >&2 echo "Fatal: ${*}"
    exit 1
 }

 function is_installed() {
    command -v "${1}" >/dev/null 2>&1
 }

 for dep in "${DEPENDENCIES[@]}"; do
    is_installed "${dep}" || panic "Missing '${dep}'"
 done

 function is_set() {
    # Use this like so:
    #
    #     is_set "${VAR_NAME+x}" || show_usage_and_exit
    #
    # https://stackoverflow.com/a/13864829

    test ! -z "${1}"
 }

 function parse_commandline() {

    while [ "${#}" -gt "0" ]; do
        local consume=1

        case "${1}" in
            -t|--ttl)
                test "${#}" -gt 1 || panic "No TTL specified."
                consume=2
                ARG_TTL="${2}"
            ;;
            -h|-\?|--help)
                ARG_HELP="true"
            ;;
            *)
                if is_set "${ARG_TARGET+x}"; then
                    panic "Unexpected paramter: \"${1}\""
                else
                    ARG_TARGET="${1}"
                fi
            ;;
        esac

        shift ${consume}
    done
 }

 parse_commandline "${@}"

 if is_set "${ARG_HELP+x}"; then
    show_usage
    exit 1
 fi

 is_set "${ARG_TTL+x}" || panic "--ttl parameter is required"
 test "${ARG_TTL}" -gt 0 || panic "--ttl must be a number greater than 0"
 test "${ARG_TTL}" -le 255 || panic "--ttl must be a number less than or equal to 255"

 function ping_target() {
    local ping_output
    ping_output=$(ping -c 1 -W 1 -t "${2}" "${1}")

    if [[ "${ping_output}" =~ From\ (.+)\ icmp_seq=[0-9]+\ Time\ to\ live\ exceeded ]]; then
        echo "${BASH_REMATCH[1]}"
    elif [[ "${ping_output}" =~ [0-9]+\ bytes\ from\ (.+): ]]; then
        echo "${BASH_REMATCH[1]} TARGET"
    else
        echo "FAIL"
    fi
 }

 red="\e[1;31m"
 green="\e[1;32m"
 reset_color="\e[0m"

 function print_results() {

    local color="${reset_color}"
    if [ "${1}" == OK ]; then
        color="${green}"
    elif [ "${1}" == FAIL ]; then
        color="${red}"
    fi

    printf "${color}%s\t%s\t%s\t%s${reset_color}\n" "${@}"
 }

 while true; do

    ping_time=$(date --iso-8601=seconds)
    ttl=1

    while [ "${ttl}" -le "${ARG_TTL}" ]; do

        ip_addr="$(ping_target "${ARG_TARGET}" "${ttl}")"
        if [ "${ip_addr}" == "FAIL" ]; then
            print_results FAIL "${ping_time}" "ttl=${ttl}" "NA"
        else
            print_results OK "${ping_time}" "ttl=${ttl}" "${ip_addr}"
        fi

        if [[ "${ip_addr}" =~ \ TARGET$ ]]; then
            # We have reached our target. We need to exit this while loop
            # because we can't go further.
            ttl="${ARG_TTL}"
        fi

        ttl=$((ttl + 1))
    done

    sleep 1

 done
	#!/usr/bin/env bash

	# LICENSE: GPLv3 - https://www.gnu.org/licenses/gpl-3.0.en.html

	set -Eeuo pipefail

	[[ "${BASH_VERSINFO[0]}" -lt 5 ]] && echo "Bash >= 5 required" && exit 1

	readonly DEPENDENCIES=(ping)
	readonly SCRIPT_NAME=$(basename "${0}")

	function show_usage() {
	printf "Usage: %s [OPTIONS...] [TARGET]\n" "${SCRIPT_NAME}" >&2
	printf " -t, --ttl\t\t\tSet ping TTL\n" >&2
	printf " -h, --help\t\t\tShow this help message then exit\n" >&2
	}

	function panic() {
	>&2 echo "Fatal: ${*}"
	exit 1
	}

	function is_installed() {
	command -v "${1}" >/dev/null 2>&1
	}

	for dep in "${DEPENDENCIES[@]}"; do
	is_installed "${dep}" \|\| panic "Missing '${dep}'"
	done

	function is_set() {
	# Use this like so:
	#
	# is_set "${VAR_NAME+x}" \|\| show_usage_and_exit
	#
	# https://stackoverflow.com/a/13864829

	test ! -z "${1}"
	}

	function parse_commandline() {

	while [ "${#}" -gt "0" ]; do
	local consume=1

	case "${1}" in
	-t\|--ttl)
	test "${#}" -gt 1 \|\| panic "No TTL specified."
	consume=2
	ARG_TTL="${2}"
	;;
	-h\|-\?\|--help)
	ARG_HELP="true"
	;;
	*)
	if is_set "${ARG_TARGET+x}"; then
	panic "Unexpected paramter: \"${1}\""
	else
	ARG_TARGET="${1}"
	fi
	;;
	esac

	shift ${consume}
	done
	}

	parse_commandline "${@}"

	if is_set "${ARG_HELP+x}"; then
	show_usage
	exit 1
	fi

	is_set "${ARG_TTL+x}" \|\| panic "--ttl parameter is required"
	test "${ARG_TTL}" -gt 0 \|\| panic "--ttl must be a number greater than 0"
	test "${ARG_TTL}" -le 255 \|\| panic "--ttl must be a number less than or equal to 255"

	function ping_target() {
	local ping_output
	ping_output=$(ping -c 1 -W 1 -t "${2}" "${1}")

	if [[ "${ping_output}" =~ From\ (.+)\ icmp_seq=[0-9]+\ Time\ to\ live\ exceeded ]]; then
	echo "${BASH_REMATCH[1]}"
	elif [[ "${ping_output}" =~ [0-9]+\ bytes\ from\ (.+): ]]; then
	echo "${BASH_REMATCH[1]} TARGET"
	else
	echo "FAIL"
	fi
	}

	red="\e[1;31m"
	green="\e[1;32m"
	reset_color="\e[0m"

	function print_results() {

	local color="${reset_color}"
	if [ "${1}" == OK ]; then
	color="${green}"
	elif [ "${1}" == FAIL ]; then
	color="${red}"
	fi

	printf "${color}%s\t%s\t%s\t%s${reset_color}\n" "${@}"
	}

	while true; do

	ping_time=$(date --iso-8601=seconds)
	ttl=1

	while [ "${ttl}" -le "${ARG_TTL}" ]; do

	ip_addr="$(ping_target "${ARG_TARGET}" "${ttl}")"
	if [ "${ip_addr}" == "FAIL" ]; then
	print_results FAIL "${ping_time}" "ttl=${ttl}" "NA"
	else
	print_results OK "${ping_time}" "ttl=${ttl}" "${ip_addr}"
	fi

	if [[ "${ip_addr}" =~ \ TARGET$ ]]; then
	# We have reached our target. We need to exit this while loop
	# because we can't go further.
	ttl="${ARG_TTL}"
	fi

	ttl=$((ttl + 1))
	done

	sleep 1

	done