pdfsync is a technology that allows synchronization between a (la)tex file and the corresponding pdf output. It wasn't the first of its kind but certainly the best i've tried. In practice you need support by both your viewer and editor but then it's down to pressing a command or (shift/ctrl/whatever)+clicking somewhere and you are magically teleported into the other app to the spot corresponding to the one you were at on the other side. Anyone who has texed and needed to proof a doc of more than 5 pages length before will understand that this is invaluable.
For all the goodness, this had some drawbacks unfortunately: pdfsync was based on some tex primitives as opposed to being embedded into the engine, so the output under some circumstances wasn't perfect, it could change the generated rendering and it was incompatible with some popular packages (e.g. colortbl). I have never been bitten by any of these in the last 3 years but it always was a good excuse for viewers not supporting it (they are usually the end that carries the burden).
It unfortunately still has it's place as we will see shortly, so here are links to set up forward and backward search underMacOS + vim + skim, evince doesn't have it and never will which leaves you with xpdf and okular on linux, both of which aren't my favourites.
In comes synctex: It is the natural evolution of pdfsync done by the original author and has all the goodies without the down sides. Setting it up under Mac was even easier now that skim supports macvim as a preset :). Just choose MacVim under preferences>sync and put the following in your .vim/ftplugin/tex.vim (assuming you use the vim-latex suite)
let g:Tex_DefaultTargetFormat = 'pdf' let g:Tex_CompileRule_pdf = 'pdflatex -synctex=1 --interaction=nonstopmode $*' let g:Tex_ViewRule_pdf = 'Skim'
Look at this for all other MacOS related progs, mupdf, and evince. Okular just needs to be called with
okular --unique 'file.pdf#src:linenumber file.tex'(That's what i think the evince people should have done instead of using dbus. Oh, well...)
Now for the bad part, lua(la)tex + evince/okular isn't working with synctex. I filed bugs with luatex, evince and okular but i don't expect a solution for this anytime soon. :( That means i am back to pdfsync for now, since i really, really like my luatex. So have fun with that!
Edit: you need to tell vim to call okular/evince with the exact same filename that lualatex produces which is ./file
In order to do that goto compiler.vim which if you installed vim-latex in your .vim is under .vim/ftplugin/latex-suite/compiler.vim otherwise probably somewhere in /usr.
Apply this patch for okular. For evince it really depends which script you use, but read the patch and do it analogously.