I have got Mozilla Firefox installed, and am aware of the issues with nasty things like phishing scripts from images ending up in my browser's cache. And so that I don't have to just empty my cache all the time, I would like to know of its location in my computer.

I have noticed that there appears to be some sort of area for caching here:


And that there also seem to be some Mozilla Firefox related files here:


So which one of these is it? Or is there a different area for caching? Or different caches? For greater efficiency when scanning the caching areas, I would prefer to know exactly which top level directory only contains caching areas, so that I do not scan anything which is non-cache related.

Expanding of question:

I have looked at the questions which are possible duplicates of this in the comments, but then I also ask, what are these other locations with cache in their names then located in ~/.cache/mozilla/firefox/k29gs42c.default?:


What are these if not some sorts of caches? And if they are so, should I not also scan them? Or are their purposes different and thus would not possibly contain any contents from websites?

OS Information:

Description:    Ubuntu 15.04
Release:    15.04

Package Information:

  Installed: 37.0.2+build1-0ubuntu0.15.04.1
  Candidate: 37.0.2+build1-0ubuntu0.15.04.1
  Version table:
 *** 37.0.2+build1-0ubuntu0.15.04.1 0
        500 http://gb.archive.ubuntu.com/ubuntu/ vivid-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ vivid-security/main amd64 Packages
        100 /var/lib/dpkg/status
     37.0+build2-0ubuntu1 0
        500 http://gb.archive.ubuntu.com/ubuntu/ vivid/main amd64 Packages

3 Answers 3


Cache is the regular cache backend.
Cache2 is a new cache backend since Firefox 27 and onwards.
OfflineCache is the offline cache from which a resource is essentially loaded first and then it is checked if it is still fresh.
startupCache is a sort of fastload feature.

All of these are capable of holding pieces of website data.


.mozilla/firefox directory contains the settings and extensions. Here's output of mine:

$ ls .mozilla/firefox/b1ygiwi1.default/ | head      

The other directory actually contains different types of cache, as wie5Ooma already mentioned.

So if something would be going wrong, you'd might want to try altering or deleting completely whatever is in ~/.mozilla/firefox/ to restore settings to default.

There is also cache in .macromedia/Flash_Player\#SharedObjects/ which belongs to flash player if you use that, like s.ytimg.com from youtube.


This is my location for all stuff, including songs from sites .cache/mozilla/firefox/[random characters].default/cache2/entries

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