The Free Software Foundation's "diff" utilities, including "diff",
"diff3", "sdiff", and "cmp".

These utilities exist in the FreeBSD base collection, but the GNU
versions have added functionality that is sometimes useful.

Note that this port will install these utilities with a 'g' prefix,
for example gdiff, gdiff3, gcmp, but the texinfo documentation
will refer to these utilities without the 'g' prefix.

WWW: http://www.gnu.org/software/diffutils/diffutils.html