Undoing the Last Git Commit

A command so important, it deserves its own page: git reset --soft HEAD~1 The previous command undoes the last commit to git. I think this is one of those commands that I have typed many times during the last year. It’s very important to know which branch we currently are on, but sometimes excitement (or stress) may make us forget checking it. If this is not enough, then you can reset your branch to master like this: (this will lose all your changes):

Installing Rancher on Ubuntu/Docker

On this article we are going to install a rancher server on Ubuntu. Let’s start by getting the rancher image from docker hub: sudo docker run -d --restart=always -p 8080:8080 --name=rancher-server rancher/server Go to http://ip-address:8080 and click on Add Host. It is important that you do not use a localhost address (, localhost). If you do so, and you want to add your local computer as an agent, you will not be able to reach it.

Solution: Netbeans 8 not working on Ubuntu 15.10

Netbeans is one of my beloved day to day applications. Yesterday, when I installed Ubuntu 15.10 (Wily Werewolf) on my computer, Netbeans started to hang on the startup screen, specifically at the Loading Modules phase. It took me hours looking for solutions on the internet; and reinstalling different versions of the Java Development Framework didn’t seem to help. Finally I found the following fix at an Ubuntu forum, which turned out to be very simple to apply.

Installing CentOS 7 – A Graphical Tour for Linux Beginners

If you are new on the Linux platform, I am sure you feel overwhelmed with all the different versions available. Choosing one is not an easy task, and each version has its own pros and cons. Let me tell you why I like CentOS: It is very stable It has well tested features There is a big community around it It has many large software repositories It is Part of the RedHat / Fedora family Installing CentOS Installing a new operating system may seem challenging, but CentOS has always made this task a simple one.

How to redirect stdout / stderr to a file

Redirecting all your program output to a file is very simple and can be accomplished like this: myapp > output.log This line will send all the output generated by myapp to a file named output.log. The contents of output.log will always be overwritten; but you can use a second > to append to the current content like this: myapp >> output.log As well as with output, it is very useful to redirect the stderr (standard error output) to a file rather than to the screen.

Installing Lucene/Solr on CentOS 6

This time we are going to install Solr, the super text search platform on CentOS. The installation process requires a couple extra libraries in order to work: Apache Commons Logging and SLF4J. Installing Java yum install java java -version You must have at least version 1.6 in order to run Solr. If you got Java 1.5, I recommend you to follow this tutorial to get version 1.6. Installing Tomcat yum -y install tomcat6 tomcat6-webapps tomcat6-admin-webapps chkconfig tomcat6 on service tomcat6 start Use a web browser to check it is working correctly.

Installing Java 1.6 on CentOS 6

Java 1.5 is the default Java version you get when you ask yum to install it on CentOS. However, several applications need 1.6 in order to run. Just follow the next steps to install it. Remove Java 1.5 yum remove java-1.5-* Install the rpmforge repository cd rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt Check if you have a 32 or 64 CentOS version uname -a For 32 versions (i686) download and install the following repository

iptables snippets

iptables is the default firewall you see on any linux computer. It works by allowing (ACCEPTing) or denying (DROPing) connections to the local computer. There are basically three scenarios you can deal with: INPUT: Connections generated from a different computer targeting yours; for example, when you run a web server on your computer and others want to connect to it. OUTPUT: Connections generated from your computer targeting other computers; for example, when you open a web page or open a remote ssh session.

How to connect to MySQL from a remote server

In few words, you have to configure MySQL to allow remote connections, create a user for connecting and setup your firewall to allow it. You don’t have to do this if you are only connecting from a local application like WordPress. You need root permissions to perform the following commands.  Configuring MySQL Edit the MySQL configuration file. nano /etc/my.cnf Allow connections from all your network interfaces by commenting out the following line:

Installing MongoDB/PHP Driver on CentOS 6

Since the module is not included with the default PHP installation, you have to download it from the official repository: cd mkdir mongo-php-driver cd mongo-php-driver curl https://codeload.github.com/mongodb/mongo-php-driver/zip/master > mongo-php-driver-master.zip Unzip it unzip mongo-php-driver-master.zip cd mongo-php-driver-master You need _phpize _to build the module. You can install it from the remi repository: wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm rpm -Uvh remi-release-6.rpm yum --enablerepo=remi install php-devel Configure and build phpize ./configure make all sudo make install Make sure the installation directory is the same as the PHP extension directory by running: