Introduction In this tutorial, we’ll show you how to setup a free TLS/SSL certificate for your website on a CentOS 7 Linux server running Apache web server software.  Let’s Encrypt provides an easy way to obtain and install trusted certificates for free, and this process can be completely automated on CentOS 7 with free “certbot” software. … Read More

Disabling IPv6 on CentOS 7.5 is easy. This method was tested on a virtual server running in DigitalOcean and persists after reboots. First, let’s check to see that IPv6 is in fact enabled in a default CentOS 7.5 virtual server: [root@server ~]# ifconfig -a | grep inet6 inet6 fe80::xxxx:xxxx:xxxx:xxxx prefixlen 64 scopeid 0x20 inet6 ::1… Read More

MongoDB can be used to count documents per year, or per month, etc. In traditional SQL, this would be accomplished via a COUNT and “GROUP BY” clause. In MongoDB, this can be accomplished like so: db.pictures.aggregate( { “$project”: { “y”: { “$year”: “$picture_datetime.taken”, }, “m”: { “$month”: “$picture_datetime.taken”, }, } }, { “$group”: { “_id”:… Read More

There’s no GUI option to export an OVA (Open Virtual Appliance) format VM in VMware fusion, but there is a command-line method. Use the OVF tool. The following provides a command-line synopsis. $ cd /Applications/VMware\ Fusion.app/Contents/Library/VMware\ OVF\ Tool/ $ ./ovftool –acceptAllEulas \ > /Users/me/Documents/Virtual\ Machines.localized/TheVM.vmwarevm/TheVM.vmx \ > ~/Desktop/TheVM.ova Opening VMX source: […] Opening OVA target:… Read More

Newer versions of CentOS and Red Hat Enterprise Linux, such as CentOS 7 and RHEL 7, use a different format for Ethernet device naming.  The long names can be cumbersome and difficult for systems administrators to work with. Fortunately, Ethernet devices can be easily reverted to the old naming format: edit the /etc/default/grub file, look… Read More

We’ve written about this in the past but just discovered Rufus.  What an incredible, free and lightweight tool for creating bootable USB drives on Windows.  We’ve successfully used it to create both Linux and Windows bootable images from a Windows 10 workstation.  It also runs on 32-bit and 64-bit versions of Windows 7 and Windows… Read More

Converting WAV files to good GSM files for use with Asterisk is easy if you have the `sox` program installed.  Most online forum postings recommend using the “resample” option, but this is deprecated in newer versions of the `sox` program.  Instead, the following command can be used to easily convert a WAV file to GSM format for… Read More

Computers, like everything, age with time.  When transferring files from an old computer (whether for friends, family or customers), it is often much easier to connect the hard disk from the old computer to a Linux workstation instead of going through the trouble of booting up the old computer and trying to salvage the data using the old… Read More

While not included in the Base Operating System (“BOS”), the bash shell can be installed on AIX. The first step is to use the built-in RPM command to install one of the more-current RPMs from IBM’s OSS repository: aix# rpm -Uvh ftp://public.dhe.ibm.com/aix/freeSoftware/aixtoolbox/RPMS/ppc/bash/bash-4.2-3.aix6.1.ppc.rpm The next step is to actually enable the shell. Typically, on Linux, this… Read More

After installing a fresh copy of AIX 7.1, one of the first things most people want to do is connect to it via SSH. In order to do so, we must first install the SSH software. The good news is that doing this is quite simple. 1. Put the AIX installation DVD #1 of 2… Read More