Do I need adb? Whats wrong with terminal? I'm pretty new to Android, but I have a bit of linux understanding.
Do I need to use adb and do I need to type adb before every command?

I have SSHDroid running on my GS3. I open my regular linux terminal and did ssh root@&lt;ip&gt;. When I got in I typed abd logcat, that failed. just logcat worked.

I'm happy with the shell I know, is this going to cause an issue?
The answer depends on what you want to do. ADB and SSH serve different purposes, though they have some things in common: you can remotely access your Android device, and execute commands on it. With ADB you can do a lot more -- you will get an idea if you read the ADB tag wiki and also follow the links contained there.
One more thing in common: both can be used interactively.
And one more shorty: they do not depend on each other.
SSH
To use SSH, you will need to install a SSH server on your Android device. If the latter is rooted (as a Linux user, I do not need to explain that &quot;root&quot; is the administrative account, and also known as the &quot;super-user&quot; who has full access to everything), you can set it up to use the default SSH port -- otherwise you need to chose one above 1000, as it is with Linux.
Now you can interact with the device: copy files with scp, or log in to the device directly. This way you reach a shell, and can work on the device like on any other Linux machine (almost -- of course there are some restrictions, like e.g. no X-Server being present, and a limited set of commands).
ADB
With ADB you can also establish such a &quot;terminal mode&quot;, by simply executing the command adb shell without any arguments. This directly brings you to the shell prompt. Similar to ssh, you can also directly execute commands by simply pass them as parameters. In this case, as with ssh, you will be returned to your local terminal prompt once the command has been completed.
ADB offers additional commands, not only &quot;shell&quot;. So you can e.g. use adb push or adb pull to transfer files (comparable to scp). All the other capabilities go beyond the scope of your question -- but above mentioned tag wiki should get you started here as well.
One last word on ADB: similar to SSH, this is a client-server model. Which means, to execute ADB commands from a client, you must have a server running. This is started when you enable &quot;USB Debugging&quot; in the settings of your Android device.