sudo gem*

Rails: Omniauth-oauth2 gem for Linkedin, Twitter, Facebook is not working

If you’re using a Devise gem and the latest Omniauth Oauth2(1.4.0) for authentication chances are you may encounter an errors below:

How to display environment variables in a terminal ?

How to display environment or system variables in your terminal ?
For Linux: 
$ printenv — Print all or part of environment.
$ env — Print all exported environment or run a program in a modified environment.

Rails: Specified ‘mysql2’ for database adapter, but the gem is not loaded. Add `gem ‘mysql2’` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord).

Git: Basic commands

How to add and commit a 
add & commit
 You can propose changes (add it to the Index) using
git add {filename} or git add .
git commit -am “Commit message”
 Now the file is committed to the HEAD, but not in your remote repository yet.

Print the Linux $PATH in readable format

[sourcecode language=”bash”]
$ echo $PATH | sed ‘s/\:/\n/g’ | sort
Output:
/bin
/home/artheman/.nvm/versions/node/v6.2.2/bin
/home/artheman/.pyenv/bin
/home/artheman/.pyenv/shims
/home/artheman/.rbenv/bin
/home/artheman/.rbenv/plugins/ruby-build/bin…

HTTP Token Authentication workflow

Sample API workflow.

Step 1)
[sourcecode language=”bash”]
curl -k -X GET “https://mysampleapp.com/api/info?id=3727&apiKey=48254c477c&user=johndoe@mysampleapp.com" \
-H “Content-Type: application/json” \
-H “Authorization: Basic…

Load balancing configuration (round robin) haproxy.cfg

[sourcecode language=”bash”]
# global parameters
global
 # log on syslog of 127.0.0.1 udp port 514 (default) using local0 facility. 
 log 127.0.0.1 local0
 
 # maximum number of concurrent connections
 maxconn 4096
 
 # drop privileges…

Node.js — npm ERR! Error: EACCES: permission denied, mkdir ‘/home/artheman/.npm

Problem:

I cannot install a semantic-ui using npm. When I encounter an error like this usually the solution is using a sudo command. Please don’t ever use npm with sudo…

How to install php curl ?

[sourcecode language=”bash”]
### First, check if there is enabled curl.
$ php info | grep -i curl

### If no result then install the php curl library
$ sudo apt-get install php5-curl

Mongoose: CastError: Cast to ObjectId failed for value \”583fe2c488cf652d4c6b45d1\” at path \”_id\” for model User

Recently I encountered this mongoose error CastError: Cast to ObjectId failed for value \”583fe2c488cf652d4c6b45d1\” at path
 \”_id\”…

Mongoose: TypeError: hex is not a function

If ever you’ve encounter an error that says “
TypeError: hex is not a function
 at Function.from (native)
 at Function.from (native)
 at new ObjectID…

Git: How to create a pull request

Steps on creating a Pull request into the master branch

1. git checkout -b {branchName}
2. git commit -am ‘your message here’
3. git push origin {branchName}
Example:
[code language=”bash”]
# Create a local…

Related sites and tutorials

Adding ESLint with gulp.js for React.JS

[sourcecode language=”bash”]
$ npm install babel-eslint — save-dev 
$ npm install gulp — save
$ npm install gulp-eslint — save
[/sourcecode]
gulpfile.js will contains like this:
[sourcecode language=”javascript”]
var gulp = require(‘gulp’);
var eslint =…

Ubuntu Commands

How to preview video or image thumbnails in Ubuntu ?
$ sudo apt-get install ffmpegthumbnailer
It works also in Ubuntu Mate

Docker cheat sheet

### To show Container information like IP adress.
docker inspect {containerId/name}

### To show log of a Container. 
docker logs {containerId/name}

ruby/rails: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

Problem:
[sourcecode language=”bash”]$ gem install sass
ERROR: Could not find a valid gem ‘sass’ (>= 0), here is why:
 Unable to download data from…

Git: error: pathspec ‘develop’ did not match any file(s) known to git

Problem: error: pathspec ‘develop’ did not match any file(s) known to git.
$ git clone blah..blah..blah
$ git branch
* master
From master branch you switch to develop
$ git checkout develop
error: pathspec…

Git: How to set email address on Git repo

You can configure an individual repo to use a specific user / email address which overrides the global configuration. From the root of the repo, run
[sourcecode language=”bash”]
$ git config user.name “Arman Ortega”
$ git config user.email your@email.com