texdoc is a tool that helps you find and view documentation in texlive. Its primary function is to locate relevant documentation for a given keyword (typically, a LaTeX package name) on your hard disk, and open it in an appropriate viewer. For instance, say that you want to view the documentation for the package
biblatex, then you issue the following in a terminal
If you use auctex you can access
texdoc via C-c ? (or M-x TeX-doc).