# Where are the biblatex macros defined?

Today I wanted to modify some of `biblatex`'s bibliography driver macros (in my special case it was the `url+urldate` macro). My plan was to copy the macro from the `biblatex` package of my `TeX` distribution to my document preamble and modify it. My first way went straight to the `standard.bbx` file where the default bibliography style is defined.

Unfortunately I had to find out that not all of the macros that are called via the `\usebibmacro` command are defined in the `standard.bbx`. As the `standard.bbx` is something like the base style that `biblatex` relies on, I could also find no hint that some other style file is required or relied on, where those macros could be defined.

Therefore my questions: Where are those commands defined, that are used in the `.bbx` files, if they are not defined neither in the `.bbx` itself nor in the `standard.bbx`? Is there a simple way to find out, where those macros are defined?

I tried some of the solutions from How to find out where a macro is defined? but those don't seem to work for `biblatex`'s `bibmacro`s.

• `url+urldate` (like some other bibmacros) is located in `biblatex.def`. – lockstep Mar 27 '13 at 22:27
• @lockstep Great, thanks for the fast solution! – Benedikt Bauer Mar 27 '13 at 22:35

@lockstep has given the answer already but (depending on your operating system) (this is actually bash on windows/cygwin) you can use a combination of `kpsewhich` and grep to answer such questions.
`````` grep url.urldate  \$(dirname `kpsewhich biblatex.sty`)/*
``````/usr/local/texlive/2012/texmf-dist/tex/latex/biblatex/biblatex.def:\newbibmacro*{url+urldate}{%