First of all, it is important to know how did you install TexLive:
- As a package from your linux distribution.
- What distribution?
- What version of TexLive?
- Directly from TexLive.
My installation of TexLive is the second one, TexLive 2012, and the file subfiles.sty is located at:
$TEXLIVE_HOME/texmf-dist/tex/latex/subfiles/subfiles.sty
So, if you installed from your distribution, you have two options:
- If using Debian (or Debian based distros), install
texlive-latex-extra as pointed out by @egreg.
- If using other distros, try to search a good match with the respectiv package manager.
- If you prefer to have a more up-to-date LaTeX distribution, think about installing TexLive2012 from the link above.
UPDATE 1:
As you are using Linux Mint, this problem is very strange, because if you execute in a terminal:
apt-cache show texlive-latex-extra
you can find subfile package in the list.
UPDATE 2:
According to packages.debian.org, the location of subfiles.sty should be this:
/usr/share/texlive/texmf-dist/tex/latex/subfiles/subfiles.cls
Not your desired solution, but my humble advice:
I use Linux Mint debian edition at home (and Debian at work), but on both systems I have TexLive2012 installed by hand, in a custom directory, so I cannot tell you what happens with the distro packages.
Haven't you thought about installing TexLive directly with install-tl?:
I hope this can help.
texlive-latex-extraif you're on Ubuntu/Debian. But only for TeX Live 2012, not in the 2009 release that you may have. – egreg Jan 28 at 20:32