Initial commit

certificate_check.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+readarray -t domain_list < domain_list.txt
+
+for raw_domain in "${domain_list[@]}"; do
+    domain=${raw_domain%$'\r'}
+
+    if [[ -z "$domain" ]]; then
+        continue
+    fi
+
+    certificate=$(
+        openssl s_client \
+            -connect "${domain}:443" \
+            -servername "$domain" \
+            -showcerts \
+            </dev/null 2>/dev/null |
+        sed -n '/-----BEGIN CERTIFICATE-----/,/-----END CERTIFICATE-----/p' |
+        sed -n '1,/-----END CERTIFICATE-----/p'
+    )
+
+    if [[ -z "$certificate" ]]; then
+        echo "Checking domain: $domain - Could not retrieve certificate"
+        continue
+    fi
+
+    expiration_date=$(printf '%s\n' "$certificate" | openssl x509 -noout -enddate 2>/dev/null | cut -d= -f2)
+
+    if [[ -n "$expiration_date" ]]; then
+        echo "Checking domain: $domain - $expiration_date"
+        echo ""
+    else
+        echo "Checking domain: $domain - Could not parse certificate"
+    fi
+done