JPEG OR PNG

You have a lot of images, and want to optimize and compress the images without losing its original quality before uploading them to any cloud or local storages? There are plenty of GUI applications available which will help you to optimize the images. However, here are two simple command line utilities to optimize images and they are:

1. jpegoptim – is a utility to optimize/compress JPEG files without loosing quality.
2. OptiPNG – is a small program that optimize PNG images to smaller size without losing any information.

Using these two tools, you can either optimize a single or multiple images at a time.

Compress or Optimize JPEG Images from Command Line

jpegoptim is a command line tool that can be used to optimize and compress JPEG, JPG and JFIF files without losing its actual quality. This tool supports lossless optimization, which is based on optimizing the Huffman tables.

Install jpegoptim in Linux

To install jpegoptim on your Linux systems, run the following command from your terminal.

Run Command Every X Second

A system administrator often needs to run a command repeatedly in a certain periods of time. Often such tasks can be easily completed with simple cron commands. In most of the cases  this should work, but the shortest period which you can run cron command is every 1 minute. Believe it or not, in many cases this is too slow.

Run Linux Command Every Second

In this tutorial, you will learn a simple scripting techniques to monitor or keep a eye on a particular command in continuously running state similar to top command (continuously monitor the process and memory utilization)for every 3 seconds by default.

We will not stop to discuss the reasons, why you would need to run commands this often. I believe everyone has different reasons for that in their daily jobs or even at home PCs and laptops.

1. Use watch Command

Watch is a Linux command that allows you to execute a command or program periodically and also shows you output on the screen. This means that you will be able to see the program output in time. By default watch re-runs the command/program every 2 seconds. The interval can be easily changed to meet your requirements.

Monitor Memory Usage

“Watch” is extremely easy to use, to test it, you can fire up a Linux terminal right away and type the following command:

# watch free -m

The above command will check your system free memory and update the results of the free command every two seconds.

RHCE

Dear friends,

The Tecmint.com team is pleased to announce that a long-awaited request from you has become a reality: the availability of the RHCSA (Red Hat Certified System Administrator) and RHCE (Red Hat Certified Engineer) ebook in PDF format.

Let us tell you why we decided to invest time, effort, and resources to provide you with this possibility.

Besides being committed to providing you with high-quality content, we take great pride in helping spread the knowledge of Linux and Free Open Source Software (FOSS) because 1) we believe in the philosophy, and 2) as part of our world-wide family, we want to help you advance in your career as much as we can.

RedHat RHCSA and RHCE Certification Exam Study Ebook

This ebook, along with the official Red Hat Enterprise Linux 7official guides, will help you prepare to take and pass theRHCSA (EX200) and RHCE (EX300) exams. As you know, both exams are aimed at determining if your knowledge, skills, and ability to meet those required of a junior and senior administrator, respectively, of RHEL 7 systems across a wide variety of environments and scenarios.

Becoming RHCSA and RHCE certified can help you show to potential employers (and current as well) that you have what it takes to contribute to the success of their IT departments, which ultimately means the overall success of the business.

Additionally, demand for highly qualified Linux professionals with certifications is continually on the rise. But do not take our word for it – let’s take a look at a few well-known online job board sites where RHCSA and RHCE related positions have been posted recently.

At the time of this writing (mid February, 2016), here are the number of open positions available in each site (click on the numbers to go to the search page with results):

SITE	RHCSA – Job Positions	RHCE – Job Positions
Monster.com	309	487
Monsterindia.com	64	64
Naukri.com	31	697
Indeed.com	475	769
Careerbuilder.com	23	47

As you can see, if you get a Red Hat certification, you are not likely to be left without job opportunities.  [full_width]

Top Linux Software

As 2015 draws to a close, it is time to share a list of the best 20 Free and Open Source Software I found during this year. Some of these programs may not be new in that they weren’t released for the first time in 2015, but they are new and have been helpful to me. It is in the spirit of sharing that I’m writing this article hoping you find some of these programs useful as well.

Best Free Open Source Softwares of 2015

To begin, you may want to search for the program using your distribution’s package manager, like so:

Fedora and derivatives:

# yum search all package
Or
# dnf search all package

Debian and derivatives:

# aptitude search package

OpenSUSE and derivatives:

# zypper search package

Arch Linux and derivatives:

# pacman -Ss package

If your search returns no results, head over to the website of each tool where you will find the standalone package for download and installation instructions, along with information on dependencies.

Top Linux Distributions

A brief comparison with 2014 will also help us whether those distros are actually experiencing sustained growth or not. Ready to start? Let’s begin.

10 Top Linux Distributions of 2015

To find out what are the most widely used distros of this year, let’s head to Distrowatch and check the Page Hit Ranking (PHR for short) table. There you can choose a wide variety of time spans that will allow you to check the ranking of Linux and BSD distributions in that period of time.

To begin, let’s take a look at the following comparative table, which lists the position of the top 10 Linux distributions from this year and from 2014:

POSITION	2015	2014
1	Linux Mint	Linux Mint
2	Debian	Ubuntu
3	Ubuntu	Debian
4	openSUSE	openSUSE
5	Fedora	Fedora
6	Mageia	Mageia
7	Manjaro	Arch
8	CentOS	Elementary
9	Arch	CentOS
10	Elementary	Zorin

As you can see, there hasn’t been much or remarkable changes during this year. Let’s now take a look at the 10 top Linux distributions with the highest ranking as per Distrowatch, in descending order, as of December 9, 2015.

Install VLC

t was written by the VideoLAN project and can be available for all operating platforms such as Windows, Linux,Solaris, OS X, Android, iOS and other supported operating systems.

Install VLC Player in RHEL/ CentOS / Fedora

It also has compression feature for many audio and video files and ability to stream media files over computer network. For more information and features can be found at http://www.videolan.org/vlc/features.html

This is our ongoing Best Linux Players series, in this article, we will show you how to install latest version ofVLC Media Player in RHEL 7/6, CentOS 7/6 and Fedora 23-20 systems using third party repositories with Yumautomated package installer.

Install VLC Media Player in RHEL/CentOS and Fedora

VLC program doesn’t included in the Linux operating systems, we need to install it using third party repositories like Epel and Nux Dextop. With the help of these repositories we can install list of all updated packages automatically using YUM package manager tool.

Install EPEL and Nux Dextop Repositories on RHEL/CentOS

First, install Epel and Nux Dextop repository for your Linux OS distribution using following links. Please select and install it according to your Linux supported system versions.

For RHEL/CentOS 7

# rpm -Uvh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
# rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm

For RHEL/CentOS 6

------------------ On 32-Bit Systems ------------------
# rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
# rpm -Uvh http://li.nux.ro/download/nux/dextop/el6/i386/nux-dextop-release-0-3.el6.nux.noarch.rpm

------------------ On 64-Bit Systems ------------------
# rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# rpm -Uvh http://li.nux.ro/download/nux/dextop/el6/x86_64/nux-dextop-release-0-2.el6.nux.noarch.rpm

Installing RPMFusion Repository on Fedora

Under Fedora distributions, the RPMFusion repository comes as pre-installed, if not you can follow below commands install and enable it as shown:

For Fedora 23-20

# yum localinstall --nogpgcheck http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm 
# yum localinstall --nogpgcheck http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

Check the Availability of VLC in RHEL/CentOS/Fedora

Once you’ve all the repositories installed on your system, do the following command to check the availability ofVLC player.

# yum info vlc
# dnf info vlc         [On Fedora 23+ releases]

Sample Output :

Loaded plugins: fastestmirror, langpacks, versionlock
Loading mirror speeds from cached hostfile
 * base: mirror.nbrc.ac.in
 * epel: kartolo.sby.datautama.net.id
 * extras: mirror.nbrc.ac.in
 * nux-dextop: li.nux.ro
 * remi-safe: remi.check-update.co.uk
 * rpmforge: kartolo.sby.datautama.net.id
 * updates: mirror.nbrc.ac.in
Available Packages
Name        : vlc
Arch        : x86_64
Version     : 2.2.1
Release     : 6.el7.nux
Size        : 1.5 M
Repo        : nux-dextop/x86_64
Summary     : The cross-platform open-source multimedia framework, player and
            : server
URL         : http://www.videolan.org
License     : GPLv2+
Description : VLC media player is a highly portable multimedia player and
            : multimedia framework capable of reading most audio and video
            : formats as well as DVDs, Audio CDs VCDs, and various streaming
            : protocols. It can also be used as a media converter or a server to
            : stream in uni-cast or multi-cast in IPv4 or IPv6 on networks.

Installing VLC Player in RHEL/CentOS/Fedora

As you see the VLC player is available, so install it by running the following command on the terminal.

# yum install vlc
# dnf install vlc       [On Fedora 23+ releases]

Starting VLC Player in RHEL/CentOS/Fedora

Run the following command from the Desktop terminal as normal user to Launch the VLC player. (Note : VLC is not supposed to be run as root user).

$ vlc

VLC Player Preview