Texpipeline
Texpipeline allows the conversion of (La)TeX documents with simple filter pipes such as:
cat input.tex | tex2pdf > output.pdf
It removes the hassle of running (La)TeX again and again, leaving lots of auxiliary files in the current directory. This is especially useful for programs which create LaTeX files automatically and just want to present the PDF output to the user.
For managing hand-typed LaTeX documents, latex-mk might be better suited.