first commit

profiles/base/.local/bin/check_ip

@@ -0,0 +1,85 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o pipefail
+set -o nounset
+
+readonly SCRIPT_NAME="${0##*/}"
+
+check_deps() {
+    command -v "curl" >/dev/null 2>&1 || die "curl: command not found"
+}
+
+usage() {
+    cat <<EOF
+Usage: ${SCRIPT_NAME} [--family auto|4|6] [-h|--help]
+
+Query an external service using curl and print:
+  1) public IP address
+  2) reverse DNS (PTR record)
+  3) curl version
+
+Options:
+  --family auto|4|6   select IP protocol version (default: auto)
+  -h, --help          show help and exit
+EOF
+}
+
+shell_quote() {
+    local -r string="$1"
+    printf "'%s'" "${string//'/'\\''}"
+}
+
+die() {
+    local -r message="$1"
+    printf "%s: %b\n" "${SCRIPT_NAME}" "${message}" >&2
+    exit 1
+}
+
+invalid_option() {
+    local -r option="$1"
+    die "invalid option $(shell_quote "${option}")\nTry '${SCRIPT_NAME} --help' for usage."
+}
+
+parse_args() {
+    family="auto"
+    while (( $# > 0 )); do
+        case "$1" in
+            -h|--help) usage; exit 0 ;;
+            --family)
+                ( (( $# < 2 )) || [[ -z "$2" ]] ) && die "--family requires an argument (auto, 4 or 6)"
+                family="$2"
+                shift 2
+                ;;
+            --family=*)
+                family="${1#*=}"
+                [[ -z "${family}" ]] && die "--family requires an argument (auto, 4 or 6)"
+                shift
+                ;;
+            *) invalid_option "$1" ;;
+        esac
+    done
+    validate_args
+}
+
+validate_args() {
+    case "${family}" in
+        auto|4|6) ;;
+        *) die "invalid value for family: '${family}' (expected auto, 4 or 6)"
+    esac
+}
+
+show_ip() {
+    local -a curl_args=()
+    [[ ${family} == "4" ]] && curl_args=( "-4" )
+    [[ ${family} == "6" ]] && curl_args=( "-6" )
+    curl "${curl_args[@]}" "zx2c4.com/ip"
+}
+
+main() {
+    check_deps
+    parse_args "$@"
+    show_ip
+}
+
+main "$@"