Firefox has a convenient function in its Bookmark Manager (Bookmarks / Bookmark Managerr). Once you’ve opened BookMark Manager, which opens in a new window, just click on File, Export and choose where to save the bookmarks file. By default, the file titled bookmarks.html.
Of course, if you ever need to restore the file — or to import it into a new Firefox installation — there is a similar Import function there.
That makes it easy to back up the Firefox bookmarks. It also makes it very easy to take a copy of them with you — on a floppy disk, a CDROM or a USB Flash Drive, or on any type of memory card (Compact Flash, Memory Stick, SD/MMC card, etc) if you have a card reader to take along.
I usually do it the hard way, though — just out of habit because early browsers didn’t export and import well. Plus, my way, I always have a backed up copy from my nightly backup across my network using Karen’s Replicator Firefox actually stores the bookmarks all in one file, which you can even open with your web browser. You might need to know that, if somehow Firefox becomes corrupted and you are unable to get it to start up or to export the bookmarks.
Read more in Backing Up Your Firefox Bookmarks
