Pack Unpack Jar

sudo service stop
cd /opt/tomcat/webapps
sudo mkdir tmp; cd tmp
sudo jar -xvf ../myapp.war
#make edits...
sudo vi WEB-INF/classes/templates/fragments/header.html
sudo vi WEB-INF/classes/application.properties
#end of making edits
sudo jar -cvf myapp0.0.1.war *
sudo cp myapp0.0.1.war ..
cd ..
sudo chown tomcat:tomcat myapp0.0.1.war
sudo rm -rf tmp
sudo service start

Bulk unfollow people on LinkedIn

If you are using chrome go the page that shows who you are following (LinkedIn) and run this code in the chrome developer console. It will go and click the unfollow button for you. I had to scroll down on the page first so all the profiles would load before I ran the script.

var buttons = $("button"),
interval = setInterval(function(){
 var btn = $('.is-following');
    console.log("Clicking:", btn);
    btn.click();
    if (buttons.length === 0) {
     clearInterval(interval);
    }
}, 1000);

http URL not calling in Angular

Http uses rxjs and is a cold/lazy observable, meaning that you should subscribe to it to make it work.

  this.http.get(`http://swapi.co/api/people/1`).map((response:Response) => {
                console.log(response.json());
                response.json();
            }).subscribe();

Or if you want to subscribe from somewhere else , you should return the http.get method like this : :

 getAllPersons():Observable<any>{
    console.log("Here");
       return this.http.get(`http://swapi.co/api/people/1`).map((response:Response) => {
        console.log(response.json());
        response.json();
    });
    } 

and then :

   getAllPersons().subscribe();

building and Deploying Google Firebase cloud functions

https://firebase.google.com/docs/functions/get-started

$ firebase deploy --only functions

$ firebase deploy --only functions:addMessage

Cannot set variable of undefined

https://stackoverflow.com/questions/38807643/error-uncaught-in-promise-typeerror-cannot-set-property-isadmin-of-null

when variable not set in function "then" block, this doesnt work, need to a copy of "this" reference with in the calling function.

down voteaccepted

Either you can use arrow function firebase.database().ref('/userProfile/' + user.uid).once('value') .then((snapshot) => { or use var self = this; firebase.database().ref('/userProfile/' + user.uid).once('value') .then(function(snapshot) { self.isAdmin = true; otherwise this doesn't point to the current function when it's called. See also https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Functions/Arrow_functions

promise-polyfill error while using Firebase in Angular

ERROR in ./~/firebase/app/shared_promise.js

Module not found: Error: Can't resolve 'promise-polyfill'

Solution: 
npm install promise-polyfill --save-exact

continuous integration | angular cli + firebase + travis ci

https://houssein.me/continuous-integration-angular-firebase-travisci