Monthly Archives: February 2018

Install COMODO Postive SSL certificate on Ubuntu

Comodo offers a wide range of SSL certificates to suit a diverse range of business requirements and budgets.

Follow below steps to install comodo positive ssl certificate on your ubuntu server.

Step 1 –  Before applying for a certificate we need to submit Certificate Signing Request (CSR)  to Certificate Authority (CA). Run below command on your server

* replace example_com with your domain name if you want to

It will ask following details

  • Organization Name
  • Organizational Unit
  • Country Code
  • State / Province
  • Locality
  • Common Name – This is the domain name for which you want to purchase SSL certificate

After providing above mentioned details this command will create two files

  • example_com.key – Your private key which you need to configure Apache or Nginx
  • example_com.csr – CSR

Step 2 – Apply for the certificate and provide content of CSR file

Step 3 – After submitting CSR, CA will send you an email on email selected by you. You should get your SSL certificate after verifying your domain.

Your certificate zip file will contain

example_com.crt  – Your ssl certificate
AddTrustExternalCARoot.crt – Root CA certificate
COMODORSAAddTrustCA.crt  – Intermediate CA certificate
COMODORSADomainValidationSecureServerCA.crt  – Intermediate CA certificate

Step 4 – Create a bundle of all crt files

Step 5 – Configuring Apache web server to serve website over HTTPS

Step 6 (Optional) – Configure Nginx to serve website over HTTPS

Install or update nodejs usin NVM in Ubuntu

Node JS is a JavaScript runtime built on Chrome’s V8 JavaScript engine. Node.js uses an event driven, non-blocking I/O model that makes it lightweight and efficient
 Using nvmNVM, which stands for “Node.js version manager” we can install multiple versions of nodejs on Ubuntu.

To install or update nvm, you can use the install script using cURL: ( You can find the installation instructions on projects github page

or using Wget:

Run the script by running 

To get the list of available Node.js versions

React Native Issues

Recently I started learning React Native to build native mobile applications using React JS. I faced lots of issues while making my first application run on my Ubuntu desktop. Here I am recording issues I faced and the solutions that worked for me, so that beginners like me don’t have to reinvent the wheel.

A problem occurred configuring project ‘:app’.
> SDK location not found. Define location with sdk.dir in the file or with an ANDROID_HOME environment variable.
  1. Go to your React native Project -> Android
  2. Create a file
  3. Open the file
  4. paste your Android SDK path like below
    • in Windows sdk.dir = C:/Users/USERNAME/AppData/Local/Android/sdk
    • in macOS sdk.dir = /Users/USERNAME/Library/Android/sdk
    • in linux sdk.dir = /home/USERNAME/Android/Sdk

Replace USERNAME with your user name

Now, Run react-native run-android in your terminal
ENOENT: no such file or directory, open ‘android/app/src/main/assets/’
Manually create this directory
mkdir android/app/src/main/assets
Unable to load script from assets
  1. (in project directory) mkdir android/app/src/main/assets
  2. react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/ --assets-dest android/app/src/main/res
  3. react-native run-android

ou can automate the above steps by placing them in scripts part of package.json like this:



Then you can just execute npm run android-linux from your command line every time.

I will keep updating this as and when I encounter new issues with solutions that worked for me.