Bash Archives - Sysadmins of the North

My New Hugo Site created in WSL 2 on WIndows 10

Hugo development environment in WSL 2

Windows Server / By Jan Reilink / 25 July 2020 19 August 2020

How to install and configure Hugo for static site development in WSL on Windows 10.

Do you find it too difficult to install Go or Hugo in Windows for your static site development? Have you tried Windows Subsystem for Linux (WSL) 2? Using a default Ubuntu 20.04, it is pretty easy to install Hugo, set up your development environment and configure Hugo to listen on your Ubuntu’s IP address instead of localhost / 127.0.0.1. This makes your Hugo development site accessible for browsers in Windows 10. Neat, right?

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Bash function to generate a random alphanumeric string

GNU Linux / By Jan Reilink / 21 February 2020 18 July 2021

Create a random string in Bash easily. 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.

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Restore single MySQL table from a full mysqldump backup file

MySQL / By Jan Reilink / 21 August 2017 19 February 2020

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.

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Release hold queue email in Postfix – postsuper

GNU Linux / By Jan Reilink / 6 August 2017 3 September 2021

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 to maintain your mail servers.

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Benchmarking WordPress, simple load & speed testing with ApacheBench

WordPress / By Jan Reilink / 9 October 2016 2 April 2020

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 can shed some light.

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Recursive scp and symlinks

GNU Linux / By Jan Reilink / 4 February 2016 9 November 2020

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!

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Generate pseudo-random passwords with OpenSSL

GNU Linux / By Jan Reilink / 27 November 2015 6 March 2020

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…

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Tunnel RDP through SSH & PuTTY

Windows Server / By Jan Reilink / 28 April 2015 10 September 2021

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 there is no VPN available to the remote network… Here is how to set up a RDP SSH tunnel with PuTTY.

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Turn off swap

GNU Linux / By Jan Reilink / 25 March 2015 7 July 2020

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…

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Monit monitoring on Ubuntu 14.04 VM on Hyper-V

GNU Linux / By Jan Reilink / 15 February 2015 27 July 2020

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 14.04 VM, built on Hyper-V. And we use Monit to monitor several websites, and send out notifications on downtime.

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How to restore a deleted Open-Xchange context?

GNU Linux / By Jan Reilink / 21 January 2015 8 February 2019

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 backups of course.

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Convert decimal to hex in Bash?

GNU Linux / By Jan Reilink / 6 November 2014 7 September 2021

A quicky for my archives: convert decimal to hex in Bash, and convert hexadecimal to decimal, in Bash. 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, B, C, D, E, F (or alternatively a-f) to represent values ten to fifteen. If you want to convert hexadecimal values to decimal and decimal values to hexadecimal, here’s how. All on the bash prompt…

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How to delete all MAILER-DAEMON emails in Postfix queue

GNU Linux / By Jan Reilink / 4 June 2014 3 September 2021

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 messages never leave your queue. In Postfix, there are various similar commands to delete messages from the Postfix mail queue. Based on the Message-ID and/or email address…

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Minify JavaScript, CSS and compress images

WordPress / By Jan Reilink / 18 May 2014 18 March 2020

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, CSS, and JavaScript can speeds up your website because of smaller and faster downloads, parsing, and execution time.

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How to test SMTP Authentication and StartTLS

Security / By Jan Reilink / 17 May 2014 15 September 2021

How to test SMTP authentication and StartTLS using the command line?

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.

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