I copied the
qtree.sty file to my
/usr/share/texmf-texlive/tex/latex directory (pretty much everywhere there, in
base/ even in
qtree/) but when I run Lyx and insert the following command LaTeX Preamble:
I keep getting
You should not put it in the main tree, but rather in the local tree:
The first command tells the system to create the required structure; the second one copies the file, the third finally tells the TeX system where to find it.
sudois not the way you act as a superuser, then use the proper method for your operating system.