In the world of the net this is old news, but poor advice is still out there, so duty calls, though in this case it's not contradiction of a factual error, just those who err by providing poor advice.
That poor advice is to add the "daily ppa" (a "repository" for software that holds test versions of the programs) to your "sources" (of software) "list" in Ubuntu in order to add Firefox 4 to a pre- 11.04 version distribution, i.e. Maverick Meerkat or Lucid Lynx (I am not sure whether this will work for 9.10). The trouble with the daily repository is that it's the source for testing versions of software, not stuff meant for general end-users, and doing so may destabilize your system.
Examples offering this poor advice:
[insert almost all results of potential Google searches for upgrading to Firefox 4.0 on Ubuntu 10.10, 10.04 LTS, 9.10, that is, Maverick Meerkat, Lucid Lynx, and Karmic Koala]
The frustration includes that the popular Linux distribution has little viable means for end-users to upgrade programs to current versions that aren't released by the distribution vendor itself (Canonical), and that Ubuntu 10.10 shipped with Firefox 3.6 (http://www.webupd8.org/2010/08/ubuntu-1010-to-ship-with-firefox-36.html) rather than Firefox 4.0 rc1, despite that Ubuntu has shipped beta revisions of the browser's earlier incarnations and that 4.0 has many major improvements not only in presentation, but behavior on the system: releasing memory being one such major improvement to the plumbing.
Other advice for adding Firefox 4.0 includes downloading a "tar.bz2" (for those intimidated, just think of ".zip") archive, extracting it to the appropriate directory, and creating the appropriate "symlinks" (comparable to shortcuts) to make the program appear in system menus or on the desktop (http://www.johannes-eva.net/how-to-install-firefox-on-ubuntu-linux, http://www.socialblogr.com/2010/09/how-to-install-firefox-4-on-ubuntu-without-losing-the-old-version.html), but that creates another problem, the problem of a program added to the system without the oversight and care of the "package manager" to manage any necessary upgrades and/or additions in the future, something the general end-user shouldn't be troubled with.
To elucidate, the same issues that make Linux poor from the perspective of independent software vendors as opposed to distributors of the OS, and the perspective of users who want to upgrade the software of independent vendors without the need to wait on their distributor, are also the reasons behind Linux being lighter, and for the convenient central repositories to grab software such as "Synaptic", one example of the "package managers" which oversee the system; adding software outside of such managers without expertise will mean that conflicts or problems could arise upon such managers performing their tasks later; in essence, the manager is left out of the loop of vital information when software is installed manually.
The team at Mozilla, however, has a better way. This has appeared (I think I remember it as being) on Slashdot and a few other sites (e.g. http://compixels.com/6344/how-to-install-firefox-4-in-ubuntu-maverick-lucid). Instead of adding the "daily ppa" of Ubuntu which will destabilize the system, Mozilla has a ppa for stable builds of Firefox
ppa:mozillateam/firefox-stableOne can enter
apt-get-repository ppa:mozillateam/firefox-stable [first word of current distro code-name] mainin a terminal window to add it, or else go to the GIU software center and follow
EDIT > Software Sources > Other Software > Addand enter
ppa:mozillateam/firefox-stable [first word of current distro code-name] mainin order to utilize the Mozilla repository. Aftwards, one must update the sources, i.e. follow
System > Administration > Update Manager and click "Upgrade", and then can grab Firefox 4.0 from the software center or Synaptic. (One can also add the repository in the Synaptic GUI itself, btw.)
By [first word of current distro code-name] is meant "maverick" or "lucid"; for 9.04, e.g. if you're running "Maverick Meerkat" (10.10), the entry you'll need is
ppa:mozillateam/firefox-stable maverick mainand if "Lucid Lynx" (10.04) it is
ppa:mozillateam/firefox-stable lucid mainRemember that whether letters are upper or lower case matter!
The "signing key" and "fingerprint" may also be needed, found here, https://launchpad.net/~mozillateam/+archive/firefox-stable.
By avoiding the Ubuntu daily ppa your system won't be exposed to the instability of those test packages; by adding this ppa to one's system's software sources and upgrading through Synaptic (my preference) or a system built on top of it (the Software center) the upgrade is performed by the system, changes are tracked by the package manager, and so it will be able to avoid and resolve future conflicts that might otherwise have arisen.
related Google Searches:
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upgrading Ubuntu 10.10, 10.04 LTS, 9.10 Maverick Meerkat, Lucid Lynx, and Karmic Koala to Firefox 4
upgrading Firefox 3.6 to Firefox 4 in Ubuntu 10.10, 10.04 LTS, 9.10 Maverick Meerkat, Lucid Lynx, and Karmic Koala
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