You can use this Bash function in your .bashrc file to generate a random alphanumeric string. This comes in handy when you need to generate a long, secure password for example. Adjust to your needs. Jan ReilinkMy name is Jan. I am not a hacker, coder, developer or guru. I am merely a systems administrator,…
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If you need to restore a single table from a full MySQL backup, you may find yourself wondering “how do I do that?”. There are a few steps required, I outline them here for you to restore the contents of just one table back into the database from the mysqldump using Bash. Jan ReilinkMy name…
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How to flush Postfix’ mail queue from the command line and delete all mail from the queue? Easy, use the Postfix postsuper command as explained in this post. The postsuper command controls different types of queues in the Postfix mail system, like the deferred or hold queue. This post shows you some Postfix queue operations…
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WordPress load testing with ApacheBench. ab is a small benchmark utility that comes with Apache. It’s a really simple HTTP load generating tool, ideal for a simple WordPress load & speed test. How fast does your WordPress site respond? How many HTTP requests per second can your server handle? These are questions on which ab…
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Recursive scp without following symbolic links. TL;DR: when using recursive scp, symbolic links aren’t preserved and are copied as if they are normal directories. So you have to look for another solution to recursively transfer symlinks over ssh. Here is one: Tar over ssh! Jan ReilinkMy name is Jan. I am not a hacker, coder,…
OpenSSL comes in handy when you need to generate random passwords, for example for system accounts and services. In this short post I’ll give you a quick example on how to generate random passwords with OpenSSL in Linux (Bash), Windows and PHP… Jan ReilinkMy name is Jan. I am not a hacker, coder, developer or…
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How to tunnel Remote Desktop (RDP) over SSH with PuTTY. Have you ever been in a situation where you needed to perform remote administration on a Windows Server, and the RDP port 3389 is blocked on a firewall? Did you know you can tunnel RDP over SSH with PuTTY? This particularly comes in handy when…
Not every Linux server I maintain needs to have a swap partition and to start swapping. For instance, the MySQL servers all have more than enough RAM on board to do their work. Yet, when a swap partition is enabled Linux starts swapping, which may degrade MySQL database performance… Jan ReilinkMy name is Jan. I…
In this post you’ll learn about setting up a Monit monitoring service for your websites and services. Monit is a free and open source service monitoring application which can perform various event-based actions. Monit can send email notifications, restart a service or application, or take other responsive actions. We set Monit up on a Ubuntu…
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How-to restore, or recover, an accidentally deleted OX context. If you’ve accidentally deleted an Open-Xchange context (contextid), then that is bad… Here is how to recover a deleted OX context and filestore… Assuming you make Open-Xchange backups of course.
A quicky for my archives: Convert decimal to hex in Bash, and hexadecimal to decimal. In mathematics and computing, hexadecimal (also base 16, or hex) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0-9 to represent values zero to nine, and A,…
How to delete all MAILER-DAEMON emails from your Postfix queue, when it matches a sender or recipient email address condition. When a large scale spam run was sent through your mail servers, you need to clean up and remove those spam messages. Doing so guarantees normal, valid email messages being sent quickly, and the spam…
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Fire-and-forget JavaScript and CSS minification and PNG image optimization on the Linux-, Mac OS X and Windows command-line interface. Using OptiPNG and YUI Compressor Optimize PNG images and minify JavaScript and CSS files, the easy and fast way? With YUI Compressor and OptiPNG on the Windows-, Linux- and macOS command line of course! Compacting HTML,…
When investigating SMTP authentication issues, particular over TLS encrypted SMTP connections, it’s always handy if you are able to test the SMTP authentication and StartTLS connection. Preferably from your command line. This post shows you how to test SMTP servers, verify SMTP authentication and StartTLS encrypted connections from the Linux and Windows command line. Jan…
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How to use shorthand names for hostnames with ssh? You don’t always want to type in a complete host name when using ssh to remote hosts. Here is how to configure and use shorthand hostnames with ssh. Jan ReilinkMy name is Jan. I am not a hacker, coder, developer or guru. I am merely a…
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