This is what happens when I try to install asciidoc:
$ sudo apt-get install asciidoc
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
dblatex docbook-utils jadetex latex-beamer latex-xcolor libgraphite3
libkpathsea6 libptexenc1 lmodern luatex pgf prosper ps2eps tex-gyre texlive
texlive-base texlive-bibtex-extra texlive-binaries texlive-common
texlive-doc-base texlive-extra-utils texlive-font-utils
texlive-fonts-recommended texlive-fonts-recommended-doc
texlive-generic-recommended texlive-latex-base texlive-latex-base-doc
texlive-latex-extra texlive-latex-extra-doc texlive-latex-recommended
texlive-latex-recommended-doc texlive-luatex texlive-math-extra
texlive-pictures texlive-pictures-doc texlive-pstricks texlive-pstricks-doc
tipa xmlto
As far as I understand, it is completely unnecessary for the html and docbook backends: I would only need it if I want to generate latex files.
This question is related to this question, in the sense that it is not easy to install vanilla Tex Live on a Ubuntu / Debian (this is necessary for getting up-to-date versions of Tex Live components, sometimes).
