Some days ago one of my sites certificate expired. I didn’t pay attention to the Let’s Encrypt periodic warning emails – I’m using the DNS-01 challenge.
I must create a simple script to check how many days are left and install it as a cron job.
After some search I found that
date could do it.
$ curl https://thejoyofstick.com -vI --stderr - | grep "expire date:" | cut -d: -f 2-
Jun 25 17:26:52 2022 GMT
$ date --date='Jun 25 17:26:52 2022 GMT' '+%s'
$ date '+%s'
$ echo '(1656178012-1649805603)/86400' | bc
We now have a way to calculate how many days are left.
You can build a bash script with these and, after checking for a countdown days threshold, send yourself a proper alert email.
For myself I’m using a perl script based on this one
use strictures 2;
use Date::Simple ( 'date', 'today' );
my $site = shift || 'example.com';
my $client = IO::Socket::SSL->new("$site:443")
or die "error=$!, ssl_error=$SSL_ERROR";
my $cert = $client->peer_certificate();
my $time = Net::SSLeay::X509_get_notAfter($cert);
my $asn_t = Net::SSLeay::P_ASN1_TIME_get_isotime($time);
my ($date) = split /T/, $asn_t;
my $diff = date($date) - today;
my $warning_time = 15;
print "Expire date: $date\n";
print "How many days left: $diff\n";
print "Warning before $warning_time days\n";
Added a personal email module to send a message if
$diff is less than
$warning_time and then cron with it.
Update: still valid for Ubuntu 20.04 LTS and 22.04 LTS !!!
Where are the MIB files ?
I’m in the middle of upgrading old servers and I found Ubuntu starting on 12.04 didn’t install the MIB files. Even if you install the SNMP applications. It was really strange to launch
tkmib and just see a couple of nodes.
The explanation is simple. Just check the preamble of
# As the snmp packages come without MIB files due to license reasons, loading
# of MIBs is disabled by default. If you added the MIBs you can reenable
# loaging them by commenting out the following line.
Sure, but how can I install them ?
Fortunately there is a package to deal with that.
$ sudo apt-get install snmp-mibs-downloader
It will download the IETF MIB files and install them under the usual
If for any reason you don’t see it happen force it with
$ sudo download-mibs
You can repeat this command later to update any new MIB file.
Well, almost. At this time your tools still won’t work correctly. Just remember the text on
/etc/snmp/snmp.conf. You have to comment out the
mibs : line! Now everything is by the book. Enjoy!
Install HP Support Software in your Ubuntu server
If you are using the Google repository to update your Chrome it doesn’t update anymore with
apt-get due to security reasons.
Reading package lists... Done
E: Repository 'http://dl.google.com/linux/chrome/deb stable Release' changed its 'Origin' value from 'Google, Inc.' to 'Google LLC'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
The solution is fast. Just run
sudo apt update
apt and not
apt-get. And just accept the change.
Do you want to accept these changes and continue updating from this repository? [y/N]
Then just use again
sudo apt-get update and
sudo apt-get upgrade