System Code Geeks Operating System Developers Resource Center

macOS Finder offers a possibility to preview the files of any type without opening them with Quick Look. By default Quick Look supports most commonly used file formats which may not be enough if you are a developer and you want to preview source code files i.e. Java or Python or any other un-common file types. Quick Look plugins Quick ...

This is more of a reminder for myself so I don’t need to keep googling or looking at man when I need to look up the syntax. Let’s assume you have two hard drives, ones called PHOTOS the other other PHOTOS_BACKUP. You can use the following command to sychronise photos (including removing all files that were deleted on PHOTOS to ...

In this post, you will learn about listing users in Linux. Besides this, you will know other tricks about Linux users’ characteristics. There are 2 types of users in Linux, system users who are created by default with the system. On the other hand, there are regular users who are created by system administrators and can log in to the ...

Docker compose is making for me wonders when it comes to run some simple components on my workstation. Spawning and simulating an infrastructure locally is fast and takes no time. Also it is lightweight. However most teams nowadays use Kubernetes.If you want to simulate a Kubernetes environment locally the tool to use is Minikube. With Minikube you need to have ...

Have you ever deleted any important files by mistake? Who doesn’t! Okay, but can I recover them? In this post, you will learn how to recover deleted files on Linux using various programs on different file systems. You will see how to recover deleted files from SD cards, HDDs, and deleted partitions on different Linux file systems such as EXT3, ...

Recently we experienced an interesting production problem. This application was running on multiple AWS EC2 instances behind Elastic Load Balancer. The application was running on GNU/Linux OS, Java 8, Tomcat 8 application server. All of sudden one of the application instances became unresponsive. All other application instances were handling the traffic properly. Whenever the HTTP request was sent to this ...

Driving home from a long day of work, I see the beautiful sky and so to not miss the beauty, I decided to pull over to take this picture. But then coming home, I was reminded of today’s challenges and I felt that it’s best to document my findings for posterity and to share it with the rest of the ...

Thanks to Linux, we have access to many tools that facilitate networking administration & diagnostics. In this sense, the Linux ping command is one of the most useful tools for sysadmins and network administrators. Its basic function is to determine if one host of the network is reachable or not. However, in this post, we will address other more advanced capabilities ...

Every organization needs to collect logs from multiple sources in order to put them in either a log collector or SIEM (or a dedicated audit trail solution). And there are two options for that – using an agent and agentless. Using an agent is easy – you install a piece of software on each machine that generates logs and it ...