Posts in Category: Tips

Proxy using SSH Tunnel

Browse the web using your SSH Server by making it a proxy server
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How to auto start services on boot in Centos / Redhat / Oracle Linux?

To auto start services in Centos, Redhat or Oracle Linux, you can use builtin chkconfig utility. It is located in /sbin directory. If you are a regular user (non-root), then /sbin may not be in your path. Therefore, you may have to use the full path to access the chkconfig utility.


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Display calibration

As i use the same monitor (LG W2486L) on my Nintendo Wii U and my Computer, i never payed attention to the fact that sometimes i couldn’t see some colors just for a wrong calibration on my display.

I do use Adobe Lightroom on this PC to make enhancements to the photos, but how could i know if my display was showing what i need to see?

A friend of mine told me about some videos that could help me to do that, on the link below you can download the videos and check more information about it.

I just used the basic settings and now my display is very better, i can see a better range of whites and blacks.

YouTube Background for Android 2.2+

I made this app for a friend that wanted to play YouTube videos just to listen it’s audio. So it’s very simple, works by sharing the URL from YouTube video with the app or googleing the video. (for instance: go to and type “YouTube lindsey”.

Unfortunately, google removed this app from google play, so its here now.



Very cool tool for sysadmins! Check it out! 🙂

CLI Database optimization

MariaDB & MySQL:

sudo apt-get install mysql-client
mysqlcheck -h yourdatabasehost -u root -p --auto-repair --check --all-databases
mysqlcheck -h yourdatabasehost -u root -p --auto-repair --optimize --all-databases


vacuumdb -afvz -h yourdatabasehost -U postgres
reindexdb -a -h yourdatabasehost -U postgres
*updated* November, 04, 2021
Docker example:
docker exec -it postgres-server vacuumdb -afvz -U postgres

Check you website performance

WebPageTest, GTmetrix, PageSpeed Insights and Website Grader can test your website and your webserver and helps you to see if you are using optimal configurations!

GNU/Linux cli image optimizer

There are some benefit from lossless recompression utilizing optipng for PNGs, gifsicle for GIFs and jpegoptim for JPGs. Optimized graphics transfer faster and provide a faster perceived response for clients. The following example will recursively optimize (without any loss of quality) all the graphics and image files on a server with the above commands installed and available.


sudo apt-get install optipng gifsicle jpegoptim imagemagick

Then execute this lines where you want to optimize your files. Remember to use the same owner user of those images.

find . -iname *.png -exec optipng -o7 --strip all {} \;
find . -iname *.gif -exec gifsicle -O2 -b {} \;
find . -iname *.jpg -exec jpegoptim --strip-all --max=85 {} \;
find . -iname *.jpg -exec convert -interlace line -quality 80 {} {} \;

For WordPress, you can install EWWW Image Optimizer or WP

Source: Moodle