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. Related to this, I have a custom prompt that shows a random smiley and the current git branch to the prompt.

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 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.

Installing MongoDB on CentOS 6

The first step is to configure the repositories. Create the following file /etc/yum.repos.d/10gen.repo with the following contents: For 32-bit systems: [10gen] name=10gen Repository baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/i686 gpgcheck=0 enabled=1 For 64-bit systems: [10gen] name=10gen Repository baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/x86_64 gpgcheck=0 enabled=1 Install Mongo yum install mongo-10gen mongo-10gen-server  Configure MongoDB You can configure Mongo by editing the following file: /etc/mongod.conf Set Mongo to autostart on system boot: chkconfig mongod on Start Mongo service mongod start Stop Mongo

How to setup a FastCGI development environment in CentOS 6

Install the development environment Install the C/C++ development tools to your server: yum install gcc gcc-c++ autoconf automake Now, before installing fcgi we need to add the epel repository: rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-7.noarch.rpm Once it is installed we can proceed to get the fcgi packages: yum install fcgi-devel spawn-fcgi Let’s see if we can compile a simple file. Create a file named example.c and copy and paste the following code in it:

One-liner to minimize your CSS files

The following one-liner will help you remove comments, spaces, and more from your CSS files. Suggestions are always welcomed. Important: Before running this command, create a copy of your original file. Try the resulting CSS in a test environment before releasing it. cat style.css | sed -e ' s/^[ t]*//g; # leading spaces s/[ t]*$//g; # trailing spaces s/([:{;,]) /1/g; # spaces after a colon, brace, semicolon, or comma s/ {/{/g; # spaces before a brace /^$/d # blank lines ' | sed -e :a -e '$!

Useful vim commands

Even though we have many sophisticated GUI text editors, there is one that has passed all time tests: vi. vi is a text editor created originally for Unix in 1976. Are you kidding? 1976? Why should I even bother to know it exists? Because that is the only text editor you will find for sure in any Unix like command line environment, that includes any Unix flavor, Linux and Macs. Believe me, there are many times when you have no other way to edit files (like webpages, php’s, css’s) but from the command line.