Certificate Expiration Page

I have wanted to check on expiration dates on certificates on all servers.  I created this bash script and saved it in the same location as the php page below.

#!/bin/bash
currdate=$(date +%s)
printf '%-60s %-29s %15s\n' "Hostname" "Cert. Exp. Date" "Days Remaining"
declare -a StringArray=("aaa" "host1" "host2" "host3" "www")
for val in "${StringArray[@]}"; do
  cert=$(echo | openssl s_client -connect $val.yourdomain.com:443 -servername $val.yourdomain.com 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "$val..com" "$cert" "$((moredays)) day(s) remaining"
done
# This section is for servers without the default SSL/TLS port of 443 or IP addresses
cert=$(echo | openssl s_client -connect admanager.yourdomain.com:8444 -servername admanager.yourdomain.com 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "adaudit.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"
cert=$(echo | openssl s_client -connect admanager.yourdomain.com:8443 -servername admanager.yourdomain.com 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "admanager.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"
cert=$(echo | openssl s_client -connect server1.yourdomain.com:15443 -servername server1.yourdomain.com 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "server1.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"
cert=$(echo | openssl s_client -connect unifi.yourdomain.com:8443 -servername unifi.yourdomain.com 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "unifi.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"
cert=$(echo | openssl s_client -connect unifi-guest.yourdomain.com:8443 -servername unifi-guest.yourdomain.com 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "unifi-guest.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"
cert=$(echo | openssl s_client -connect 1.2.3.4:443 -servername 1.2.3.4 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "server2.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"
cert=$(echo | openssl s_client -connect 5.6.7.8:443 -servername 5.6.7.8 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$currdate/86400 && printf '%-60s %-30s %15s\n' "server3.yourdomain.com" "$cert" "$((moredays)) day(s) remaining"

The output was similar to this:

Hostname                                                     Cert. Exp. Date                Days Remaining
www.microsoft.com                                            Aug 21 16:01:06 2025 GMT       45 day(s) remaining
www.amazon.com                                               Jun 29 23:59:59 2026 GMT       357 day(s) remaining

In case you only want to check the certificate on one host, the following script can be used.

#!/bin/bash
read -p "Enter Fully Qualified Domain Name (FQDN) (i.e.: www.yourdomain.com): " hostcheck
read -p "Enter port number to check or hit Enter for default port of 443: " portnum
portnum="${portnum:-443}"
printf '%-60s %-29s %15s\n' "Hostname" "Cert. Exp. Date" "Days Remaining"
cert=$(echo | openssl s_client -connect $hostcheck:$portnum -servername hostcheck 2>/dev/null | openssl x509 -noout -dates | tail -n 1 | cut -d "=" -f 2) && moredays=$(date -d "$cert" +%s)/86400-$(date +%s)/86400 && printf '%-60s %-30s %15s\n' "$hostcheck" "$cert" "$((moredays)) day(s) remaining"

Finally, display it via a php page with this code

<head>
  <title>Certs Check</title>
  <link rel="icon" type="image/ico" href="Company.ico">
</head>
<?php
  $URL1=$_SERVER['REQUEST_URI'];
  header("Refresh: 900; URL=$URL1");
  $Output = shell_exec('/var/cache/www/html/Certs.sh');
  echo "<pre>$Output</pre>";
?>

Change /var/cache/www/html/Certs.sh to the path and name of your shell script.

Feel free to comment if you have a suggestion to make it simpler

Regards,

F. Bobbio C.