Every Linux user has been sooner or later trapped in a situation in which having working Backspace and Delete keys on the console and on X seemed impossible. This paper explains why this happens and suggests solutions. The notions given here are essentially distribution-independent: due to the widely different content of system configuration files in each distribution, I will try to give the reader enough knowledge to think up his/her own fixes, if necessary.
I assume that the Backspace key should go back one character and then erase the character under the cursor. On the other hand, the Delete key should delete the character under the cursor, without moving it. If you think that the function of the two keys should be exchanged, in spite of the fact that most keyboards feature an arrow pointing to the left (←) on the Backspace key, then this paper will not give you immediate solutions, but certainly you may find the explanations given here useful.
Another assumption is that the fixes should alter only local (user) files. No standard part of the distribution should be altered. Finally, this document discusses how to set up your system so that applications get the right events. If an application decides to interpret such events in an idiosyncratic way, the only possible fix is to reconfigure the application.
Note: Since the first release of this Mini-HOWTO things have become even more entangled. Different distributions of the same terminal emulator (e.g., gnome-terminal as provided by Red Hat 7.0, Helix Code/Ximian or even Red Hat≥7.1) generate different ASCII sequences. Due to this mismatch, now the terminal databases correspond even less to the terminal emulators they are supposed to describe. To set a firm ground for the following discussion, we assume basically as correct settings the ones proposed in the Debian keyboard guidelines.