rtlsdr.org wiki

Options for free software in Linux are:

• GNURadio is an excellent but unwieldy piece of software for use with RTLSDR. It's the only software for now that will receive analogue (FM, AM, sideband) and digital modes such as AP25, FSK and ADS-B. Be warned it's not very easy to drive but if you are canny you can use it to build your own software defined radio. Follow the build guide for your Linux system as the latest code is always the best to use.
• GQRX apparently does too.
• As SDR# is written in C# it works with Mono in Linux!

Have a look here for a good summary of Linux utilities.

As of September 2015 SDR# works again in Linux on x86/x64 and ARM! (yes, you can pick your jaw up off the floor). This has been tested on Linux Mint 17.2 and an Odroid UX4.

The fact that SDR# worked in Mono at all was a happy accident. The author did not intend this and is not obligated to keep the code backwards-compatible with Mono.

• Install mono 4.0.4 (or later) for your distro from here. This is the Linux version of Microsoft's .net.
• Install libportaudio2 to make sure sound works.

  sudo apt-get install libportaudio2

• RTLSDR users: I used the cmake version as detailed here. Don't forget to run ldconfig as root at the end to sort the newly installed libraries out.
• Airspy users: Download and install the host drivers from here.
• Download the latest zipfile copy of SDR#. zippetydoodah
• Unzip to a new directory.
• cd into the new SDR# directory and type the following:

  ln -s /usr/local/lib/librtlsdr.so librtlsdr.dll
  ln -s /usr/lib/x86_64-linux-gnu/libportaudio.so.2 libportaudio.so

• If the last command doesn't work type locate libportaudio.so.2 and try again with the new path. On 32 bit systems it will be in a different directory to what's shown here.
• With your favourite text editor open SDRSharp.exe.config and find the line

     <!-- <add key="RTL-SDR / USB" value="SDRSharp.RTLSDR.RtlSdrIO,SDRSharp.RTLSDR" /> -->

  and remove .net comments of so that it looks like

  <add key="RTL-SDR / USB" value="SDRSharp.RTLSDR.RtlSdrIO,SDRSharp.RTLSDR" />

  . This will enable use of the RTLSDR dongle.

• Type mono SDRSharp.exe and you should see something like the screenshot below! Ignore any exceptions that might pop up at the start that involve SDRIQ as it's complaining about hardware you don't have. Maybe the author is thumbing his nose at you. You can stop the exceptions by commenting out or deleting the lines in SDRSharp.exe.config for hardware you don't have.
• If you get audio stutter (I do on my i7 CPU!) change the audio latency from 100ms to 200ms or more. It seems Mono doesn't run SDR# anywhere as efficiently as the native Windows CLR. I have tried –optimize=all and also the –llvm options and it doesn't seem to help. Any advice appreciated!
• Be sure to select [ALSA] sysdefault as audio output, otherwise you may experience audio stutter.

Have a look here for some words on using rtl_tcp and SDR#.