# Why does the latex command sometimes produces PDF output?

I have noticed that on some .tex files (making use of the graphicx and hyperref packages and PDF image files), the latex command produces PDF files instead of the expected DVI. How and when does this happen?

In case this matters, I'm using TeXLive 2012.20120611-3~ubuntu12.04.1 on Ubuntu 12.04 (from PPA):

\$ latex
This is pdfTeX, Version 3.1415926-2.4-1.40.13 (TeX Live 2012/Debian)
restricted \write18 enabled.

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latex and pdflatex use the same executable (pdftex); you can't include PDF files when you use latex, nor should pass the pdftex option to graphicx or hyperref, which would change the output mode from DVI to PDF. –  egreg Apr 2 '13 at 11:19
Beside \usepackage[pdftex]{graphicx} (which should give an error message) it is also possible that a faulty "\ifpdf"-code in some old package sets unvoluntarly \pdfoutput=1. –  Ulrike Fischer Apr 2 '13 at 11:35

pdf(la)tex writes DVI code by default and produces PDF just if the integer register \pdfoutput is set non zero. So presumably you are loading a package (perhaps with a pdftex option) that is setting this register.