Linux Tip: Creating Shell Script Functions and Exposing Them in the Current Runtime Environment

Creating shell scripts are easy to develop at the same time hard. Imagine that you have almost all access to the kernel, services, modules and available functions. Well it's procedural but that doesn't mean you can't group applications together while specifying their run sequence and simply apply your OOP and design patterns in these "bits" of applications.

So how do you group them? You create a shell function or subroutine. Here's how

Installing Memcached From Source

If you encounter problems because of a bug in the RPM package, you can always follow these simple steps in installing memcached for your *nix system. The following steps have been tested to work against RHEL and CentOS operating systems.

See below.

Xdebug Trigger Mode: XDEBUG_PROFILE is Not Working

One of the two ways to configure profiling in Xdebug is through "trigger mode". There are at least two reasons why you wanna do it. One, you need just select which PHP pages you need profiled and two, you cannot actively enable profiling due to whatever performance issues (Xdebug or other profiler are well known to cause performance issues) your machine might have. "Xdebug Trigger Mode" works by first turning on xdebug.profiler_enable_trigger = on and then appending XDEBUG_PROFILE=1 in the URL query string the make the request. This should generate an appropriate cachegrind file

Xdebug Trigger Mode on the other hand have a few well-known issues or should I say, common configuration errors. Let's take a look at some of those that are frequently encountered.

Yum Thread Error on Virtual Private Servers (VPS)

If you see the following error below, it is a memory resource issue triggered by fastestmirror plugin of yum on VPS systems. So far, I have observed this to happen on Linux (RHEL) and CentOS VPS under OpenVZ virtual server.