86 lines
1.8 KiB
Bash
Executable File
86 lines
1.8 KiB
Bash
Executable File
#!/usr/bin/env bash
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set -o errexit
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set -o pipefail
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set -o nounset
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readonly SCRIPT_NAME="${0##*/}"
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check_deps() {
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command -v "curl" >/dev/null 2>&1 || die "curl: command not found"
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}
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usage() {
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cat <<EOF
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Usage: ${SCRIPT_NAME} [--family auto|4|6] [-h|--help]
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Query an external service using curl and print:
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1) public IP address
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2) reverse DNS (PTR record)
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3) curl version
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Options:
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--family auto|4|6 select IP protocol version (default: auto)
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-h, --help show help and exit
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EOF
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}
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shell_quote() {
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local -r string="$1"
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printf "'%s'" "${string//'/'\\''}"
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}
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die() {
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local -r message="$1"
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printf "%s: %b\n" "${SCRIPT_NAME}" "${message}" >&2
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exit 1
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}
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invalid_option() {
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local -r option="$1"
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die "invalid option $(shell_quote "${option}")\nTry '${SCRIPT_NAME} --help' for usage."
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}
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parse_args() {
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family="auto"
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while (( $# > 0 )); do
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case "$1" in
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-h|--help) usage; exit 0 ;;
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--family)
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( (( $# < 2 )) || [[ -z "$2" ]] ) && die "--family requires an argument (auto, 4 or 6)"
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family="$2"
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shift 2
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;;
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--family=*)
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family="${1#*=}"
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[[ -z "${family}" ]] && die "--family requires an argument (auto, 4 or 6)"
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shift
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;;
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*) invalid_option "$1" ;;
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esac
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done
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validate_args
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}
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validate_args() {
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case "${family}" in
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auto|4|6) ;;
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*) die "invalid value for family: '${family}' (expected auto, 4 or 6)"
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esac
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}
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show_ip() {
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local -a curl_args=()
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[[ ${family} == "4" ]] && curl_args=( "-4" )
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[[ ${family} == "6" ]] && curl_args=( "-6" )
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curl "${curl_args[@]}" "zx2c4.com/ip"
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}
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main() {
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check_deps
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parse_args "$@"
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show_ip
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}
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main "$@"
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