efficiency, don't apt update again if already done

updatemirror.sh

@@ -2,6 +2,10 @@
 
 set -euo pipefail
 
+function apt_update_if_stale () {
+    [ -z "$(find /var/lib/apt/lists -type f -mmin -30 2>/dev/null)" ] && apt-get update
+}
+
 function main () {
     # check for ubuntu only
     if ! grep -qi '^ID=ubuntu' /etc/os-release; then
@@ -25,34 +29,25 @@ function main () {
     find /etc/apt/sources.list.d/ -type f -exec \
       sed -i "s|archive\.ubuntu\.com|us.ubuntu.com|g" {} +
 
-
-    UPDATED=0
-    if ! which jq > /dev/null; then
-        echo "jq not found, installing..." > /dev/stderr
-        if [[ "$UPDATED" -eq 0 ]]; then
-            apt update
-            UPDATED=1
-        fi
-        apt install -y jq
-    fi
-
-    if ! which curl > /dev/null; then
-        echo "curl not found, installing..." > /dev/stderr
-        if [ "$UPDATED" -eq 0 ]; then
-            apt update
-            UPDATED=1
-        fi
-        apt install -y curl
-    fi
+    apt_update_if_stale
+    apt install -y jq curl
 
     echo "Detecting actual country..." > /dev/stderr
 
     IPINFO="$(curl -s ipinfo.io)"
+
     if [ -z "$IPINFO" ]; then
         echo "Failed to get IP info" > /dev/stderr
         exit 1
     fi
+
     COUNTRYCODE="$(jq .country -r <<< "$IPINFO")"
+
+    if [[ -z "$COUNTRYCODE" ]]; then
+        echo "Failed to get country code" > /dev/stderr
+        exit 1
+    fi
+
     echo "IP geolocated as country: $COUNTRYCODE" > /dev/stderr
 
     if ! grep -qE 'http(s)?://us\.archive\.ubuntu\.com/' /etc/apt/sources.list.d/*; then