user6219: I use Linux(Mint Linux Petra) and will probably switch to Ubuntu 14 soon.
I need to record video with my camera on my laptop(imagine I use a web-camera for simplification) and I need to see real-time what I am shooting and record the stream.
I tried camera-app and cheese but both fail on my distribution. 
Also, I plan to use external camera for better quality, any suggestions on interfaces, etc.? I prefer to see the stream directly on my laptop screen.
(If you want to know why - it will save me some time while editing.)

user11346: Try QtCAM - An Open Source Webcam application for devices supported by UVC driver or any V4L2 compatible device. You can see the preview directly on your laptop. Their updated version has support for all USB cameras and you could download the source code from GitHub.

user18411: I would recommend Shotcut. It has become my goto editor for video in Linux.

user34829: I am using Zoom.  Login as the only user, and select record.  The sound and picture are good, ir waves in mp4, and green screen is built in if you want it.

user23144: OBS (Open Broadcaster Software) is multi-platform (OBS is widely used in video game streaming). I haven't tried it yet myself for multiple cameras, but I know it supports at least one (as many streamers put a small video of themselves playing the game on their streams) and it does real-time preview.
Edit: I did run two c920 webcams with it on Linux (Ubuntu 16.04) and it works fine.

user6210: I was going to recommend Kino which is the one I used when I needed to do that, but according to their web page the project is no longer mantained, so you can either use it the way it is or try the other software that is recommended on their web page:
Shotcut, Kdenlive, Flowblade, OpenShot, PiTiVi, LiVES, and LightWorks.

6219: <p>I use Linux(Mint Linux Petra) and will probably switch to Ubuntu 14 soon.</p>

<p>I need to record video with my camera on my laptop(imagine I use a web-camera for simplification) and I need to see real-time what I am shooting and record the stream.</p>

<p>I tried <code>camera-app</code> and <code>cheese</code> but both fail on my distribution. </p>

<p>Also, I plan to use external camera for better quality, any suggestions on interfaces, etc.? I prefer to see the stream directly on my laptop screen.
(If you want to know why - it will save me some time while editing.)</p>
 11346: <p>Try QtCAM - An Open Source Webcam application for devices supported by UVC driver or any V4L2 compatible device. You can see the preview directly on your laptop. Their updated version has support for all USB cameras and you could download the source code from GitHub.</p>
 18411: <p>I would recommend Shotcut. It has become my goto editor for video in Linux.</p>
 34829: <p>I am using Zoom.  Login as the only user, and select record.  The sound and picture are good, ir waves in mp4, and green screen is built in if you want it.</p>
 23144: <p>OBS (Open Broadcaster Software) is multi-platform (OBS is widely used in video game streaming). I haven't tried it yet myself for multiple cameras, but I know it supports at least one (as many streamers put a small video of themselves playing the game on their streams) and it does real-time preview.</p>

<p>Edit: I did run two c920 webcams with it on Linux (Ubuntu 16.04) and it works fine.</p>
 6210: <p>I was going to recommend <a href="http://www.kinodv.org/" rel="nofollow">Kino</a> which is the one I used when I needed to do that, but according to their web page the project is no longer mantained, so you can either use it the way it is or try the other software that is recommended on their web page:</p>

<p>Shotcut, Kdenlive, Flowblade, OpenShot, PiTiVi, LiVES, and LightWorks.</p>
