Fedora:

rpm -ql firefox

This query will give you a lot of information (you might want to pipe it to less). What you want to zero in on is the directory that is referenced most, on my system it’s /usr/lib/firefox-1.5.0.9/. You’ll notice a lot of references to /usr/share/ and can pretty much ignore them. That directory holds icons, .desktop files and other shared objects.

I did the same for SeaMonkey (rpm -ql seamonkey), the install location for the current version of the monkey is /usr/lib/seamonkey-1.0.7/.

Ubuntu:

dpkg -L firefox

That’s another command that will hand you TONS of information. Again, I only care about the installation directory, I know from using Ubuntu that the standard application install location is /usr/lib/[installdir]. So to clean up the output, I used grep to filter out the data I don’t need (you could do the same on the Fedora example above).

dpkg -L firefox |grep /usr/lib

That gave me something that looked like:

/usr/lib
/usr/lib/firefox
/usr/lib/firefox/firefox
/usr/lib/firefox/libgfxpsshar.so
/usr/lib/firefox/libgkgfx.so
/usr/lib/firefox/libgtkembedmoz.so
/usr/lib/firefox/libgtkxtbin.so
/usr/lib/firefox/libjsj.so
[snip]

From that I can see that Ubuntu installs Firefox to /usr/lib/firefox.

I also use SeaMonkey on Ubuntu, but I had to manually install it. For that reason, dpkg has no clue as to where the software is. I chose to install it to /usr/local/seamonkey, which is the location that the SeaMonkey installer suggests. I just keep that in the back of my mind or I could enter a locate seamonkey. That will return a lot of hits as well and will look something like:

/usr/bin/seamonkey
/usr/local/seamonkey
/usr/local/seamonkey/install.log
/usr/local/seamonkey/registry
/usr/local/seamonkey/libplds4.so
/usr/local/seamonkey/libxpcom.so
/usr/local/seamonkey/libmozz.so
[snip]

Now that I know where my browsers are installed to, I can run the Flash installer and give it the correct path to each browser when asked.