Compass doesn't yet fully support the MongoDB query language. So in order to explore all CRUD operations in MongoDB, we're going to need to install the Mongo Shell. The Mongo Shell is a text based client that we'll be using by means of whatever command line interface you have available to you on your system. In this lesson, we'll take a look at how to install the Mongo Shell on a Mac OS X system. If you're on Windows, please see the video for installing the Mongo Shell on Windows systems. Now to install the Mongo Shell, we're actually going to go ahead and just install all of MongoDB Enterprise Server. Enterprise Server is bundled with a number of executables that are part of the MongoDB ecosystem, including the Mongo Shell. So please visit the MongoDB download center, you can get there with a single Google query. Click the Enterprise Server tab, and then select your operating system. In this case, we want to select OS X 64. Now please follow these installation instructions, even if you already have a version of MongoDB installed. Earlier versions of the Mongo Shell did not support SSL, and we need SSL support in order to connect to Atlas clusters. Once you've selected your operating system, click download. Now you might see a contact form pop up. If you do see a contact form, please complete it, and then download Enterprise Server. Once the download completes, we can open the Finder and navigate to Downloads. Here's the file we just downloaded, I'm going to move it to my home directory. Now if I navigate to my home directory, we can see the file right here. I'm going to double-click it, and unpack the archive file. Then if I look inside this folder I can see that there is, in addition to some licensing information, a bin directory that contains a number of executable files. The executable file we are interested in is this one, mongo. This is executable for the Mongo Shell. Please don't confuse this with mongod, mongod is the executable for the MongoDB server itself. So when we say that we have a MongoDB deployment running, it's running one or more mongods. Again, we're interested in the Mongo Shell or the mongo executable. Please place the download that you've unpacked into your home directory, as I've done here. That will make following these instructions a little simpler. Now in order to conveniently run the Mongo Shell, we're going to have to update our PATH environment variable. The PATH tells OS X where to look for programs that we'd like to run. You can set your PATH in a hidden file called .bash_profile. If I open up Sublime Text and select Open, I can see hidden files on my Mac by typing Cmd+Shift+Dot. Then if I navigate to my home directory, I can see that there is, in fact, a .bash_profile. Now on your system, you might not have a .bash_profile. If you haven't created one previously, you probably don't. Don't be alarmed if you don't see one. You can easily create one by simply creating a new file in your favorite text editor, and then saving it as .bash_profile. Make sure that you save it in your home directory. Don't save it on the desktop, don't save it anywhere else. Make sure you save it in your home directory. You can simply click Save, and a .bash_profile file will be created for you. I already have one, so I'm simply going to open the one that I have. Again, it's Cmd+Shift+Dot to see hidden files. And there's my .bash_profile, again, in my home directory. If I open this, we can see that there is one bash command in here. This command sets the prompt for my terminal application. Now in order to use the Mongo Shell, we're going to run it from a command line interface. The terminal application ships with Mac OS X, so that's the one that I'm going to use. And one thing I'll point out here is that you can see my prompt is dollar and then a space. That's because my bash profile specifies that the prompt for terminal, or for any bash shells, should be dollar followed by a space. A dive into bash, a dive into using command line interfaces other than the Mongo Shell is a little bit outside the scope of this course. So if you'd like to dive deeper on this, there are any number of tutorials on bash and the terminal application. Or, if you're on Windows, the Command shell or PowerShell. Any number of tutorials available online that I would encourage you to take a look at. So in order to run the Mongo Shell conveniently, we want to setup our PATH environment variable. When you have a Terminal application open, at any point you can look at environment variables that have been set. For example, if I'd like to see what PS1 is, I can do that simply by typing echo $PS1. You must use the $ character in order to stipulate that you want to see the value of that environment variable that's defined. I can do the same thing with the PATH environment variable. And here I can see that it is setup to some standard system directories where executable files or programs are found. This is so that I can run a number of commands from the terminal, including a number of system programs that make the command line interface really work for me. What I'd like to do is update our PATH to include the location where we just put MongoDB. As a reminder, that's in my home directory under this folder and inside the bin subdirectory. Now I've got an existing PATH, that's all of this, and I don't want to blow that away. So I need to make sure that in updating my PATH, I maintain all of those directories as well, as part of the PATH. The way we do that is through a command like this. So here I'm saying, as the value of the PATH environment variable, use this sequence of directories. So this simply means my home directory, and then with in my home directory, that long download name for MongoDB. And just as a convenience, don't try to type it, because you'll probably screw something up. Just right-click and select Copy, and that will copy the name of that directory for you, and then you can easily paste it in. So my home directory, the name of the download/bin, okay? And then, you'll see that I have a colon here. That colon says everything that follows is another directory in which to look for executable programs. So what this is saying is anytime a user requests to run a program, look for that program first in Shannon's home directory, mongodb-osx-x86_64-3.4.6/bin. So look here first, and then, if you don't find it there, continue on looking in other directories. Now by specifying $PATH here, don't forget the $, what we're saying is take all of these directories, note that they're all separated themselves by colons, and put them here. The PATH is always searched in order, so this will be searched first, and then each of the directories that are listed following this directory, following this colon, will be searched in sequence afterward. I'm asking you to put the directory we just downloaded first in your PATH so that if you happen to have a prior installation of MongoDB, when attempting to run the Mongo Shell Because the first place the system will look is in that directory we just downloaded, that is the version of the Mongo Shell that will be run, not some version that you installed previously. So if we save this, then our bash profile is updated with the new PATH. The last thing that I need to point out about this is that your PATH in the terminal won't be updated until the next time you launch a terminal, or unless you run a special command. So if I echo $PATH again, we'll see that it's exactly the same as it was before. However, it I type source ~/.bash_profile, what that does is reads my bash profile that I just updated.. And then, if I echo $PATH, now we see that that new directory we added is included in the path. What this does for us is ensures that all of these executable files can be found if we type their name here in the shell. So now if I type mongo, and I'm going to add the --nodb command line option, and you see that? What happened is exactly what I cautioned you against. And that is that I haven't correctly specified that folder in which our downloaded version of MongoDB exists. So I'm going to go back into the Finder, and I'm going to select Copy. And then I'm going to go back into Sublime, and I'm going to update my PATH with the correct value. I'm going to save it, and then I'm going to source bash profile again. And now if I check my PATH, we can see that it's been updated correctly. And now if I run Mongo, I can see that it does in fact start up for me. What we've walked through here is how to download MongoDB Enterprise package. We've talked about the fact that the Mongo Shell is bundled with the Mongo server and a number of other executables. We've walked through how to setup our PATH environment variable so that we can run the Mongo Shell from anywhere. And I've cautioned you against a couple of things that can go wrong when we're trying to set up the PATH. So it turns out that, given the steps we followed, we actually have both the correct version and the incorrect version here in our PATH. Because we were simply concatenating whatever was here onto the front of what was already the PATH. But don't worry because if I simply start up a new shell, you'll see that just the correct one is there. So on new invocations of the Terminal application, I'll pick up exactly what I want from my PATH, and I'll be able to run nodb. We look at a few more tips about how to use the Terminal application and go a lot deeper into how to use the Mongo Shell in other lessons. One last thing before we close this lesson is that if you have any trouble at all installing MongoDB on your OS X environment, please visit the MongoDB documentation for detailed instructions on installing MongoDB Enterprise. In addition to OS X, there are detailed instructions for installing MongoDB Enterprise on Linux and all the various flavors of Linux, and on Windows. And again, the Windows installation is covered in another lesson.
