Composer/Laravel: How to add/update a specific package

Question

How do you add/update a specific package using composer? I'm using the latest Laravel as well not sure if it matters but anything that can help to determine the answer.

I have also tried the following from an old Stackoverflow post I had found, but it didn't work for me. It appended the package to composer.json and then proceeded to update everything anyways. Here is the link: How to update a single library with Composer?

And here is the package I tried to add to my project: https://github.com/barryvdh/laravel-dompdf

Thank you very much for your time and help!

Edit:

---

Require and update are not working they update everything as well. Is it possible that I'm running the command incorrectly? I'm still green behind the ears when it comes to composer :S

$ composer require barryvdh/laravel-dompdf
lease provide a version constraint for the barryvdh/laravel-dompdf requirement: *
/composer.json has been updated
oading composer repositories with package information
pdating dependencies (including require-dev)
 - Removing orchestra/testbench (v2.1.1)
 - Removing symfony/security (v2.4.3)
 - Removing symfony/translation (v2.4.3)
 - Installing symfony/translation (v2.4.6)
   Loading from cache

 - Removing symfony/http-foundation (v2.4.3)
 - Installing symfony/http-foundation (v2.4.6)
   Loading from cache

 - Removing symfony/event-dispatcher (v2.4.3)
 - Installing symfony/event-dispatcher (v2.5.0)
   Loading from cache

 - Removing symfony/debug (v2.4.3)
 - Installing symfony/debug (v2.4.6)
   Loading from cache

 - Removing symfony/http-kernel (v2.4.3)
 - Installing symfony/http-kernel (v2.4.6)
   Loading from cache

 - Removing symfony/routing (v2.4.3)
 - Installing symfony/routing (v2.4.6)
   Loading from cache

 - Removing symfony/process (v2.4.3)
 - Installing symfony/process (v2.4.6)
   Loading from cache

 - Removing symfony/finder (v2.4.3)
 - Installing symfony/finder (v2.4.6)
   Loading from cache

 - Removing symfony/dom-crawler (v2.4.3)
 - Installing symfony/dom-crawler (v2.4.6)
   Loading from cache

 - Removing symfony/css-selector (v2.4.3)
 - Installing symfony/css-selector (v2.4.6)
   Loading from cache

 - Removing symfony/console (v2.4.3)
 - Installing symfony/console (v2.4.6)
   Loading from cache

 - Removing symfony/browser-kit (v2.4.3)
 - Installing symfony/browser-kit (v2.4.6)
   Loading from cache

 - Removing swiftmailer/swiftmailer (v5.1.0)
 - Installing swiftmailer/swiftmailer (v5.2.0)
   Loading from cache

 - Removing stack/builder (v1.0.1)
 - Installing stack/builder (v1.0.2)
   Loading from cache

  - Removing patchwork/utf8 (v1.1.21)
  - Installing patchwork/utf8 (v1.1.23)
    Loading from cache

  - Removing nesbot/carbon (1.8.0)
  - Installing nesbot/carbon (1.9.0)
    Loading from cache

  - Removing monolog/monolog (1.9.0)
  - Installing monolog/monolog (1.10.0)
    Loading from cache

  - Removing symfony/filesystem (v2.4.3)
  - Installing symfony/filesystem (v2.5.0)
    Loading from cache

  - Installing symfony/security-core (v2.4.6)
    Loading from cache

  - Removing laravel/framework (v4.1.28)
  - Installing laravel/framework (v4.1.30)
    Loading from cache

  - Removing chumper/datatable (2.2.2)
  - Installing chumper/datatable (2.3)
    Loading from cache

  - Removing ivaynberg/select2 (3.4.6)
  - Installing ivaynberg/select2 (3.4.8)
    Loading from cache

  - Installing phenx/php-font-lib (0.2.2)
    Loading from cache

  - Installing dompdf/dompdf (v0.6.1)
    Loading from cache

  - Installing barryvdh/laravel-dompdf (v0.3.1)
    Loading from cache

symfony/security-core suggests installing symfony/validator (For using the user password constraint)
symfony/security-core suggests installing symfony/expression-language (For using the expression voter)
Generating autoload files
Compiling component files
Generating optimized class loader

Answer 1

I tried the following and it seemed to work for me.

You'll have to first add barryvdh/laravel-dompdf to the composer.json file. Then perform the following:

 composer update barryvdh/laravel-dompdf --lock

Answer 2

here

composer update barryvdh/laravel-dompdf

composer docs