An earlier question got several nice answers involving stdin, none of which work in Firefox 9.0.1 (Edit: because I didn't read that you had to start a new Firefox process to make them work (thanks @manatwork):
echo '<h1>hello, world</h1>' | firefox /dev/fd/0results in a new tab with the URL
file:///dev/nulland no text.
cat | firefox /dev/fd/0results in a new tab with the URL
file:///dev/nulland no text. After typing a single line of text and pressing Enter it terminates and still doesn't show anything in the new tab.
firefox <( echo '<h1>hello, world</h1>' )opens up a new tab with my profile folder, of all things.
Is there any way to make this work in Firefox 9.0.1 or newer?
As to the reason behind, it would be nice to be able to generate markup which is only stored in memory (barring swapping), and guarantee that there is no left-overs even in case of a power cut.