1
00:00:00,760 --> 00:00:02,270
[treehouse presents]

2
00:00:03,220 --> 00:00:05,680
[Quick Tips] [How to Install Gems in Ruby on Rails] [by Jason Seifer]

3
00:00:06,140 --> 00:00:07,120
Hi, I'm Jason.

4
00:00:07,120 --> 00:00:11,250
In this treehouse quick tip, we're going to talk about how to install Ruby gems.

5
00:00:11,250 --> 00:00:15,670
A Ruby gem is a library that you can use in your Ruby applications.

6
00:00:15,670 --> 00:00:18,180
It's really easy to install a gem.

7
00:00:18,180 --> 00:00:21,630
You just need to know the name of the gem that you want to install.

8
00:00:21,630 --> 00:00:25,540
In this example, I'm going to install the Bundler gem.

9
00:00:25,540 --> 00:00:31,190
The way to install a gem is by typing the word "gem" followed by a space

10
00:00:31,190 --> 00:00:36,180
followed by the word "install" and then the name of the gem that you want to install.

11
00:00:36,180 --> 00:00:38,350
I'm going to install the Bundler gem.

12
00:00:38,350 --> 00:00:43,770
After that, press "enter" and then Ruby gems will go out, download the proper gem,

13
00:00:43,770 --> 00:00:45,550
and install it onto your system.

14
00:00:45,550 --> 00:00:50,220
If you get a message about not having the proper permissions to install a gem,

15
00:00:50,220 --> 00:00:54,060
you can use the "sudo" command to install the correct gem.

16
00:00:54,060 --> 00:01:00,430
You would use the "sudo" command on systems where your version of Ruby is installed 

17
00:01:00,430 --> 00:01:06,990
globally rather than on a system like RVM or RBN where you can install gems locally 

18
00:01:06,990 --> 00:01:08,210
to your own home directory.

19
00:01:08,210 --> 00:01:11,250
I'm going to install another gem called Money.

20
00:01:14,360 --> 00:01:18,480
The gem install command will also install any needed dependencies of a gem.

21
00:01:18,480 --> 00:01:24,630
For example, the Money gem requires the i18n gem and also the json gems.

22
00:01:24,630 --> 00:01:27,970
Once you install a gem, it's really easy to use.

23
00:01:27,970 --> 00:01:34,680
First, require Ruby gems, then you can also require the gem that you just installed.

24
00:01:36,660 --> 00:01:37,730
And there you go.

25
00:01:37,730 --> 00:01:42,140
There's one other way to install gems, and that would be from a gem file.

26
00:01:42,140 --> 00:01:48,450
A gem file will be in a Ruby on Rails application or actually any Ruby application 

27
00:01:48,450 --> 00:01:49,590
that uses Bundler. 

28
00:01:49,590 --> 00:01:54,580
You specify the gem dependencies in the gem file, and then once you do that,

29
00:01:54,580 --> 00:02:01,290
you can type the word "bundle install" and then Bundler will go through and install 

30
00:02:01,290 --> 00:02:02,710
all of these gems for you.

31
00:02:09,220 --> 00:02:12,720
As you can see, it's very easy to install and use Ruby gems.

32
00:02:12,720 --> 00:02:15,480
The hardest part is finding good ones to install.

33
00:02:15,480 --> 00:02:19,780
Luckily, there are sites like RubyGems.org and GitHub for that.

34
00:02:19,780 --> 00:02:21,620
Happy coding!