Audacity has a Truncate Silence effect (Effect > Truncate Silence...) which should be able to do what you want:
There are many other alternatives in other applications - but these are for Windows or OSX. I'll list them here for other users with same question but different host/OS needs:
Pro Tools - Strip Silence
Reaper - Dynamic Split
Cubase - Cut head ...
here's another one:
+ Easy to navigate thematic organization
+ Curated generally useful incidental sounds
+ Free commercial use, provided not main focus (full license)
- relatively small collection (a couple of thousand sounds in my estimation)
This is a Community Wiki answer, feel free to add your finds...
Field Recording Databases
Freesound >> http://freesound.org/ (added by yunque)
+ Search by license, format, bitrate, sample rate, tags, etc.
+ Open project, user-based (can search similar sounds recorded by the same person).
- Variable quality.
British Library ...
In my opinion, there is no commercial art. When you produce something with the intention to sell it, it is a product and not an artwork.
So for me, the purpose is the deciding factor, if something is art or not.
As an example:
The music industrie vs. homemade music:
The music industrie engineers songs on purpose. From the start, the songs are written for ...
You may like to try out 'Fracture' by Glitchmachines:
It's a buffer effect, a multimode filter, three LFOs and a delay - basically it'll mess your sound up beyond all recognition and it's quite fun just hitting randomize to see what happens.
A bit of a work around for the doppler effect is 'Proximity' by ...