How to find package for installed file in Brew?

Question

How can I identify the package/formula for a given file, or a listing of all of a package\'s owned files, in Homebrew?

Answer 1

The package name can be determined based on the symbolic link which points to the binary (Cellar/PACKAGE/...), e.g.

$ ls -la $(which awk) # => gawk
lrwxr-xr-x 1 kenorb 28 May 20  2015 /usr/local/bin/awk -> ../Cellar/gawk/4.1.1/bin/awk

$ ls -la $(which seq) # => coreutils
lrwxr-xr-x 1 kenorb 14 Apr  8  2015 /usr/local/opt/coreutils/libexec/gnubin/seq -> ../../bin/gseq