Watch, Read, Listen
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Testing website using telnet (SSL/HTTPS)
When developping a website, you could need to send custom requests to your server so you can analyze its behavior and its responses. If you’re not using secured protocol, that’s easy, you just need to connect to port 80 (usually) on your server and send your request as: telnet www.python.org 80 GET /index.html HTTP/1.1 Host:…
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Find PostgreSQL database size
PostgreSQL is an object-relational database management system (ORDBMS). It’s a free and open-source tool available under BSD licence. Thanks to some built-in functions, you can get several information regarding database and/or table size. You will find below the main and most used examples. Database size (in octal) dbpg-# SELECT pg_database_size(‘db_1’); pg_database_size —————- 342733824 (1 line) Database size…
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Setup multiple default routes on Linux
The problem ? Your system is running on Linux with multiple physical network interface cards (NIC) and each card has its own default gateway. By default, you can only set up a single default gateway on a system. In our example, we will consider 2 NICs (eth0 and eth1) enabled with default gateway configured on…
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Download Flash Video Fragmented (F4F/F4M)
Today, for network usage optimization purposes, a lot of videos are streamed and sent to the users as fragmented packets instead of one file. According to Adobe, F4F file is Flash MP4 Video Fragment created and used by Adobe Media Server for HTTP Dynamic streaming like CloudFront, Akamai, … If you want to download this video,…
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Install VMware Tools on ESXi for Ubuntu Guest
If you want to install VMware Tools on ESXi for an Ubuntu Guest, there is two possibilities: Use the package provided on distribution (but can be not up-to-date and so not approved) Install directly from official sources provided in vSphere Client (will be automatically recognized) Use the pre-package distribution This solution is the easiest way…
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Unserialize web2py requests and allow concurrent access
With a default configuration for your web2py application, you will notice that when you are launching an action, if this one is quite long to execute, you won’t be able to open a new tab to run another request on the same application. This can be explained because when you are launching an action, your…
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Handling HTTP errors with Apache and Tomcat using mod_jk
When you are working with web server in frontend (Apache in this example) and backend application servers (Tomcat here), you may wish to customize your error pages depending on the HTTP error code returned (either from the web server or application server). Pre-requisites For the following example, you will need as pre-requisites at least those…
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How to compile and install its own Linux kernel
The Linux Kernel is the operating system kernel. It is the core of the system and provide an interface between the hardware and the software layers. Most of Linux distributions are coming with a pre-compiled and ready-to-use kernel for most of standard usage. However, some functionalities are sometimes missing in the kernel to allow the…
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Create Software RAID under Linux system
A hard drive disk is a device with limits (performance, lifetime, …) and a broken disk often leads to a data loss, and sometimes with a loss of data more or less important. In order to avoid that kind of inconvenience, there are several hardware solutions allowing disk replication, but most of time with a…
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Add a Swap File
When you’re running on a Linux System (or any Unix Operating System), it’s common to use a swap to complete and optimize the memory usage on the computer (especially for older ones). There are different ways to do that, you can: Create a swap on a full partition system (most of Linux distribution will allow…