Andromeda Computer - Ilich Blanco
Ilich Blanco

Ilich Blanco

Entusiasta de la naturaleza y apasionado de la tecnología desde que puedo recordar, inversionista y fiel creyente de la tecnología blockchain y criptomonedas. Estoy seguro que los problemas de la sociedad y la humanidad en general no serán resueltos por economistas o sociólogos si no por la mente brillante de científicos.
Website URL: http:// Email: This email address is being protected from spambots. You need JavaScript enabled to view it.





Hello again everyone! in the midst of these global circumstances hoping for the best for everyone! reminding them that what is happening is not a game and it is important to abide by the official recommendations, wash your hands, wear a mask, comply

with the quarantine, and well I hope everything goes well, God willing.

Now without further ado, this time I want to leave you with a mega collection of recent memes and video memes, as you already know is our second post with that addition. Enjoy it and see you next time!













Saturday, 21 March 2020 15:37

Fantastic Tattoos: Demon Slayer



 Demon Slayer: Kimetsu no Yaiba (Japanese: 鬼滅の刃, Hepburn: Kimetsu no Yaiba, lit. "Blade of Demon Destruction") is a Japanese manga series written and illustrated by Koyoharu Gotōge. The story follows Tanjiro Kamado, a young boy who becomes a demon slayer after his family is slaughtered and his younger sister Nezuko is turned into a demon. It has been serialized in Weekly Shōnen Jump since February 2016, with its chapters collected in 19 tankōbon volumes as of February 2020. The series is published in English by Viz Media and simulpublished by Shueisha in English and Spanish on their Manga Plus platform.










Saturday, 21 March 2020 01:45

The Man Who Gathers Memes #13




In the midst of extraordinary circumstances around the world, we ask for your collaboration! Wash your hands, avoid going outside and meet other people, wear a face mask if you must go out and gloves if possible! Good luck and we will soon overcome this pandemic together.

Now without further ado let's start !!!! laugh for a while during your quarantine.










Guys, we are going to learn about the Package installation in Linux systems from this article. Basically how to install a package ( a package is  simply same as a software in a windows environment) and uninstalling it, what is a repository, how to create/enable/disable a repository, how the package installation commands change with different Linux distributions and so on.

What is a Package ?

Basically a package is a software application in a Linux operating system. Same as in windows and Mac OS, in Linux also we can install a software in a GUI environment as well as with the command line interface.

What is a Package manager ?

There are different package managers for different Linux distributions. It is very important to remember how to use different package installation commands in a Linux system. As we all know in a windows OS, we have softwares ending with .exe extension. But in Linux, the extensions may be different. It can be having an extension like .rpm, .deb or whatever.  Actually the package manager is serving as tool which access the softwares and installing/removing/modifying them.

dpkg is used by Debian, Ubuntu and apt is also supported.
rpm is used by Red Hat, Cent OS and yum is also supported.

* Important – You should be a superuser to install packages. 

So, for here testing i’m taking two AWS EC2 Linux servers ( Ubuntu and a Red Hat ). We will take one by one.

To get to know which Linux distribution you are using, try the below command,

cat /etc/*-release




Yum package manager

What is yum ? Yum is a command we can use to get the packages installed in a Red Hat, Cent OS environments. Yum is using repositories to search and install the applications.

What are Repositories ?

Red Hat or third party repositories are used as the software sources. In a repo we include links where the package managers can search for the packages.

Simply a repository looks like below.




All repositories resides in the path “/etc/yum.repos.d“. The configuration file for yum is “/etc/yum.conf“.

From here, we will check the useful command we need to know.

1) yum repolist ( This command will list your active repositories )




2) yum repolist all ( This will list all of your repositories even it is enabled or disabled )




3) yum list installed ( This will list all your installed packages )

4) yum list vim* ( This will list installed and available packages which suits for package name )




5) yum search vim ( This also searches with package names )




yum search all  ( This gives more details than above )

6) yum info vim* ( This will display information about all the packages that suits the given name )

We can identify different parts in a package as below.

eg – vim-minimal.x86_64 : A minimal version of the VIM editor

vim-minimal – Package name
x86_64 – Architecture
*Sometimes we can see package version also with the names.
7) yum provides  ( This shows packages which contains the mentioned path names ). Not only path names, we can use application names also if we are not sure to check.
eg – yum provides tree



yum provides /var/www/html




8) yum install httpd ( This will install httpd package into the system )




yum install httpd -y ( This command will install the package without asking for entering yes or no at the end. )

9) yum update  ( This will update the package to the latest version. )
10) yum remove  ( This will uninstall the installed package )
11) yum list kernel ( This will display installed and available kernel software versions )




yum update kernel ( This will update the kernel to the latest version )

12) How to create a new repo
Go to the file location – /etc/repos.d
create your new repo – example.repo



[examplerepo] – repo id

Example Repolist – repo name
baseurl – source url
enabled – status of the repo ( can be enabled or disabled )




Apt package manager

Apt package manager is used in Ubuntu and Debian like Linux distributions.  Below listed commands would be helped.
apt actually works on a package database. The system will not know about is there are updates for the packages, if the package database is not updated. Because of this updating the package database is essential.
1) apt-get update ( This command will update the package database )
2) apt-get upgrade ( This will upgrade all the software to the latest version. )
3) apt-get install  ( This will install the package )
4) apt remove  ( This will remove the package binary file except configs)
5) apt purge  ( This will remove all files with the configuration files related to the package )
6) apt show  ( Display information about the package )
7) apt list  ( list the packages with the given name )
So, guys here are some of the basic very useful commands as in the above. You could know more than these commands with the usage.



Friday, 28 February 2020 09:27

Linux Commands: The easy way



find command is a very essential command in the linux operating system. We need to use this amazing command to find files within our system hierarchy.

In a windows operating system we can use search option very simply in the GUI. Likewise we can use find linux command here to find and grab the files as our need.

Same as other linux commands find command also having so  many command options, like to search recursively in the files, to find the files with considering modified dates, accessed dates, files considering their sizes, files considering ownerships and  permissions,  and with so many options.

Also we can use the pipeline and redirection to have the output of the find command and pass it to another operation. As an example we can type the find command to find some files and delete those files with a single linux command. For that purpose we are using pipeline with –

exec or xarg command. We will discuss about -exec later. After this we will discuss the find command and it’s examples with the options. 


Syntax –

find [location] [options] [what to find]

  • location : The directories where you need to search. This can be a single location or multiple locations.
    eg – if we need to find a file under root directory, the location should be root directory.
    So, the command should start like find /
  • options : find command has so many options to optimise the search. Will discuss on below of the article.
  • What to find : The name of the file which you need to find.
    eg – if we need to find all files having the extention of .cpp under root directory, the command should be find / -name *.cpp. Here -name is the option we used to determine the file name. If we use to find a file giving a name of the file, we must use the option name. 



How to use find command with examples.


1) find files named “example.txt” in your current location

find . -name “example.txt”


2) find files named “passwd” under root directory

find / name “passwd”



 3) find files named with case insensetively.

Guess we have two files named, Text_file and text_file. These two words differ with capital T.If we need to ignore case sensitivity we need to use option name as -iname. 

find / -name “text_file” ( Case sensitive )

find / -iname “text_file” ( Case Insensitive )



 4) find file “example.txt” under your home directory

find /home -iname “example.txt”


5) find files which having the extention of .php under your home directory

find /home -type f -name “*.php”

here -type option is used to determine the type of the file, to recognize is it a file or a directory which you are searching. if you are finding a directory the option should be -type d on the above



6) find directories named example under your home directory

find /home -type d -name “example”


7) find files in more than one location

find / /home -iname “student”

Above command find the files named student in both places of root directory and /home directory.


8) find emty files

find / -type f -empty


9) find empty directories

find / -type d -empty


10) find files which have permissions of 777

find / -type f -perm 777 

-perm option is used to determine permissions with the find command. if you want to find permissions of 644, it should be like -perm 644.


11) find files not having 777 permissions

find / -type f ! -perm 777


is used to mention NOT.

12) find files which are set to SETUID

find / -perm /u=s


13) find files which are set to SETGID

find / -perm /g=s


14) find files read only files

find / -perm /u=r


15) find files and remove them

find /home -iname “*.cpp” -exec rm -rf {} ;


We will break this command into two parts.

  •  find part is ok for you. It finds all files having .cpp extension under your home directory.
  •  -exec rm -rf {} ; This part is taking the output of the find section and executes the rm -rf command to remove the searched files.  So the output of the find command is going to store inside of {} as an input to rm -rf command and -exec option makes the command as executable.


16) find files having 755 permissions and change back to 644 permissions.

find / -iname “*.cpp” -perm 755 -exec chmod 644 {} ;


17) find files based on users

find / -iname “example” -user student

Above command finds files with example named which is owned to user student.


18) find files based on group

find / -iname “example” -group user


This finds files with name example with group name user.


19) find modified files with given dates

find / -iname “*.txt” -mtime 7

find files having .txt extention under root directory which is modified on 7 days back.

find / -iname “*.txt” -mtime +7

find files having .txt extention under root directory which is modified on more than 7 days.

find / -iname “*.txt” -mtime -7

find files having .txt extention under root directory which is modified within 7 days.

find / -iname “*.txt” -mmin 7

find files having .txt extention under root directory which is modified before 7 minutes from now.

mtime is used to mention in days and mmin is used to mention in minutes. 



20) find files which accessed on 10 days back

find / -iname “*.txt” -atime 10


21) find files which are changed on before 10 minutes

find / -iname “*.txt” -cmin 10 


22) find files with size

find / -size +50M

find files which are more than 50M in size.

find / -size +50M -size -200M 

find files which sizes are more than 50M and less than 200M.


So, we have discussed alot of options can be used with find command. You can refer the internet to find more and more.





Wednesday, 26 February 2020 13:52

How to: Install jekins on your linux

Guys, Before talking about how to install jenkins on linux, shall we discuss a little bit about actually what is jenkins ? It is a automation tool which has written in java language. It is an open source application. Jenkins helps for automation tasks and mostly used by system administrators, cloud engineers, DevOps engineers and developers.


As an example if we take running Ansible playbooks on the ansible master node itself, we can use jenkins tool for running ansible playbooks. Since jenkins is a web tool, system

administrators/DevOps can easily use it taking the advantage of it’s different types plugins for specific purposes. Jenkins is also very useful for Continuos Integration and Continous delivery

(CI/CD ). Thanks to  jenkins, developers can build and test their software projects by doing the changes continously and can take the project to the production level without any distruption to the

users because of the pre testing stages running in continous delivery.

So we are going to see different ways of how to install jenkins on Linux.


1) Install Jenkins using yum command

commands :
sudo yum update -y
sudo wget -O /etc/yum.repos.d/jenkins.repo
sudo yum install jenkins -y
sudo systemctl start jenkins
sudo systemctl enable jenkins
Note : Since Jenkins is a java application, first of all you must have installed java on your centos.



 command – sudo yum install java-1.8.0-openjdk-devel




 We can check if the port for jenkins has opened. Remember that jenkins is using port 8080 as it’s default port. But we can change it if we need. 



To access your Jenkins after the Installation, Open your web browser and got to your centos local ip

with port 8080 ( or localhost:8080 ) or if you are running a virtual machine your public ip with port 8080

could be accessed. I am here using the public ip attached to my virtual machine to get the jenkins web





As shown in the browser you need to access that /var/lib path and get the Initial Admin password.

Then Install suggested plugins and login as admin ( if needed you can create another account ).

here we go, finally we have installed jenkins.





2) Install Jenkins on a tomcat

What is tomcat ? Actually tomcat is a application server from apache foundation which executes java

servlets and renders the webpages which is having java coding. Since Jenkins is a tool build with

java, we are trying to install jenkins on tomcat.


commands :

sudo yum update -y
sudo yum install java-1.8.0-openjdk-devel
cd ~
tar xzfv apache-tomcat-9.0.0.M10.tar.gz
mkdir Tomcat9
mv apache-tomcat-9.0.0.M10 Tomcat9
cd Tomcat9/bin

Now  we have installed tomcat on one of our directories in home folder and started tomcat server. You

can check of the port 8080 has opened.

sudo netstat -plunt |grep 8080

Now open the browser with your localhost:8080 or if you are running a virtual machine then your vm

local machine ip with port 8080 or your public ip with port 8080.




 Ok, now tomcat is ready to searve for java applications. Let’s get our jenkins into tomcat.

Download the jenkins war file from this link. Jenkins war releases. I use version 2.214 ( latest war file ).

commands :

cd ~/Tomcat9/webapps




Now we will get back to the browser.

try now the url as your tomcat url/jenkins, like localhost:8080/jenkins



 See now you are running your jenkins on tomcat. You can check the java process on the server. ps -ef|grep java



 If you want to shutdown or restart the jenkins, you can do it by shutting down the tomcat node. Simply

do as below

cd ~/Tomcat9/bin

./ – this will shutdown the tomcat, so jenkins will also be shutdown

./ = this will start your tomcat and jenkins will be back online




4) Install Jenkins on a docker container

commands :

First we need to install docker engine in our centos, So follow the below

sudo yum update -y

sudo yum install -y yum-utils device-mapper-persistent-data lvm2 -y

sudo yum-config-manager –add-repo

sudo yum -y install docker-ce

sudo systemctl start docker && sudo systemctl enable docker

now switch to root user – sudo su


To verify docker, use command docker ps and docker version to check the docker version.



 Guys now we have installed docker on our centos. Now we will pull our jenkins image to our centos.






docker images



 Now i am creating a docker container from jenkins image as below



You can see that i have exposed the container to be accesible from the localhost ip from host port

8080. Open the browser and try to access the jenkins container with port 8080.




So guys we discussed how to install jenkins on centos in three different ways. Hope more articles

related to jenkins on future.



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