Command Line

Postfix Relay Host – Canonical Maps and Sender Dependent SASL

By Mike Goh August 20, 2024Developers Technical TutorialsCommand Line, ServersNo Comments

Introduction There are several mail transfer agents (MTA) for Linux, like Sendmail, Postfix, and Exim. Sendmail is one of the oldest MTAs available, but it does have some drawn-out configuration steps and is too large in my opinion. The lightweight…

How to and Benchmark of awk, grep and sed on Multiple (AND) Keywords

By Mike Goh March 5, 2023Developers Technical TutorialsCoding, Command Line4 Comments

Introduction grep is useful for searching and matching text and regular expressions in one or more files on Linux. One example is finding information in logs that is related to a particular incident. We will provide a unique identifier such…

Linux Troubleshooting Guide

By Mike Goh February 7, 2023Developers Technical TutorialsCommand Line, Servers1 Comment

Last updated 14 Nov 2024 During my learning of DevOps tools, I have encountered numerous problems. These difficulties can range from solving the dependency requirement to installing the tools themselves. The majority of solutions to issues are found on the…

Set Up SFTP Chroot Jail using OpenSSH

By Mike Goh July 29, 2022Developers Technical TutorialsCommand Line, SecurityNo Comments

Introduction You may want to use one of your existing servers as a SFTP server without subscribing to another EC2 instance. Or you would like to have multiple SFTP users/vendors on a single SFTP server to save on resources and…

Bash Script Backup MySQL Databases

By Mike Goh June 10, 2021Developers Technical TutorialsBackup, Command LineNo Comments

Introduction Back in the good old days, when Git was not invented, database administrators will use a bash script to backup their MySQL databases periodically. This method is not true anymore because GitHub, GitLab and Bitbucket provide free plans and…

Automated Checks: Send Email when Product in Stock

By Mike Goh June 29, 2020Daily Rants and Excitement BlogAutomation Tools, Command LineNo Comments

Introduction Have you ever wanted to buy that pretty dress or gadget really bad but disappointed at it being currently out of stock? Then, you check the listing once every few hours in hope to snap it up when it…

Bash Script to Sync WordPress Docker Production to Demo

By Mike Goh June 6, 2020Developers Technical TutorialsCommand Line, DockerNo Comments

Introduction After we had upgraded a website from development to production status, we will need to put up a maintenance notice if we are required to make further changes. It is unpleasant to let visitors see the down-time or on-going…

How to Resolve iptables: No chain/target/match by that name

By Mike Goh April 24, 2020Developers Technical TutorialsCommand Line, SecurityNo Comments

Introduction If you encounter such error, it means that the CONFIG_NETFILTER module was not complied in your kernel. All VPS (virtual private server) that I owned from DigitalOcean, AWS, Google Cloud and other lesser-known host providers have it by default…

How to Backup Databases and Files, Rotate and Rsync to Remote

By Mike Goh April 19, 2020Developers Technical TutorialsBackup, Command LineNo Comments

We should always schedule backups for our website files and databases but should never keep the backups only in the server which your websites and databases reside in. If you are on solid cloud providers like Amazon Web Services (AWS)…

How to Make ‘docker-compose’ Short and Quick Using Aliases

By Mike Goh April 12, 2020Developers Technical TutorialsCommand Line, DockerNo Comments

Have you at times need to type docker-compose repeatedly to bring containers up and down or to check processes while in development? Here is a neat trick to shorten docker-compose to just 2 letters dc. This is a one-time change…

Postfix Relay Host – Canonical Maps and Sender Dependent SASL

How to and Benchmark of awk, grep and sed on Multiple (AND) Keywords

Linux Troubleshooting Guide

Set Up SFTP Chroot Jail using OpenSSH

Bash Script Backup MySQL Databases

Automated Checks: Send Email when Product in Stock

Bash Script to Sync WordPress Docker Production to Demo

How to Resolve iptables: No chain/target/match by that name

How to Backup Databases and Files, Rotate and Rsync to Remote

How to Make ‘docker-compose’ Short and Quick Using Aliases

Asus Router Setup – Wifi Settings

How to Resolve iptables: No chain/target/match by that name

Create Helpdesk Ticketing System with Google Apps Script

Host Multiple Websites with jwilder nginx-proxy and letsencrypt-companion