refactor code and add fallback prompt to zsh

profiles/base/.local/bin/check_ip

@@ -1,13 +1,9 @@
 #!/usr/bin/env bash
 
-set -o errexit
-set -o pipefail
-set -o nounset
-
-readonly SCRIPT_NAME="${0##*/}"
+readonly SCRIPT_NAME=${0##*/}
 
 check_deps() {
-    command -v "curl" >/dev/null 2>&1 || die "curl: command not found"
+    command -v curl >/dev/null 2>&1 || die "curl: command not found"
 }
 
 usage() {
@@ -26,18 +22,18 @@ EOF
 }
 
 shell_quote() {
-    local -r string="$1"
+    local -r string=$1
     printf "'%s'" "${string//'/'\\''}"
 }
 
 die() {
-    local -r message="$1"
+    local -r message=$1
     printf "%s: %b\n" "${SCRIPT_NAME}" "${message}" >&2
     exit 1
 }
 
 invalid_option() {
-    local -r option="$1"
+    local -r option=$1
     die "invalid option $(shell_quote "${option}")\nTry '${SCRIPT_NAME} --help' for usage."
 }
 
@@ -48,11 +44,11 @@ parse_args() {
             -h|--help) usage; exit 0 ;;
             --family)
                 ( (( $# < 2 )) || [[ -z "$2" ]] ) && die "--family requires an argument (auto, 4 or 6)"
-                family="$2"
+                family=$2
                 shift 2
                 ;;
             --family=*)
-                family="${1#*=}"
+                family=${1#*=}
                 [[ -z "${family}" ]] && die "--family requires an argument (auto, 4 or 6)"
                 shift
                 ;;
@@ -63,7 +59,7 @@ parse_args() {
 }
 
 validate_args() {
-    case "${family}" in
+    case ${family} in
         auto|4|6) ;;
         *) die "invalid value for family: '${family}' (expected auto, 4 or 6)"
     esac
@@ -71,9 +67,9 @@ validate_args() {
 
 show_ip() {
     local -a curl_args=()
-    [[ ${family} == "4" ]] && curl_args=( "-4" )
-    [[ ${family} == "6" ]] && curl_args=( "-6" )
-    curl "${curl_args[@]}" "zx2c4.com/ip"
+    [[ ${family} == "4" ]] && curl_args=("-4")
+    [[ ${family} == "6" ]] && curl_args=("-6")
+    curl "${curl_args[@]}" zx2c4.com/ip
 }
 
 main() {