View the most recent changes for the udunits port at: udunits.darwinports.com/diff
Scroll down toward the bottom of the page to get installation instructions for udunits.
The raw portfile for udunits 1.12.9 is located here:
http://udunits.darwinports.com/dports/science/udunits/Portfile
Find related portfiles with the unique DarwinPorts.com search feature.
Check for any related Fink projects here: pdb.finkproject.org/pdb/package.php/udunits

# -*- coding: utf-8; mode: tcl; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- vim:fenc=utf-8:ft=tcl:et:sw=4:ts=4:sts=4
The udunits Portfile 56695 2009-09-01 12:57:03Z takeshi macports.org $

PortSystem 1.0

Name: udunits
Version: 1.12.9
Maintainers: takeshi
Platform: darwin
Category: science

Description: Unidata unit conversion libraray
Long Description: The Unidata units library supports conversion of unit specifications between formatted and binary forms, arithmetic manipulation of unit specifications, and conversion of values between compatible scales of measurement.

Homepage: http://www.unidata.ucar.edu/software/udunits/

Master Sites: ftp://ftp.unidata.ucar.edu/pub/udunits/ ftp://www.gfd-dennou.org/arch-large1/ucar/unidata/pub/udunits
Checksums: md5 2bf4ba7a92e4c45b9e6003a295ca4e65 sha1 06923bb345055eb1bb63560b368f776ce5e15b0b rmd160 36e904d0af0585fdd7e45ffe87643193097ea6c4
worksrcdir ${distname}/src
depends_build path:bin/perl:perl5
use_parallel_build no

patch {
reinplace "s|\$(prefix)/man|\$(prefix)/share/man|" ${worksrcpath}/port/master.mk.in
}

configure.cppflags-append "-DNDEBUG -Df2cFortran"
configure.cflags-append -fno-common

pre-destroot {
file delete ${worksrcpath}/lib/libudunits.a
}

destroot.destdir DESTDIR=${destroot} prefix=${destroot}${prefix} exec_prefix=${destroot}${prefix}

# fortran compiler does not seem to be required
# gfortran might have problem with preprocessor
#variant gcc43 conflicts g95 description {compile with gcc43} {
# depends_build-append port:gcc43
# configure.env-append FC=${prefix}/bin/gfortran-mp-4.3
# configure.env-append FFLAGS="-O2 -fno-common"
#}
#
#variant g95 conflicts gcc43 description {compile with g95} {
# depends_build-append port:g95
# configure.fc ${prefix}/bin/g95
# configure.env-append FC=${prefix}/bin/g95
# configure.env-append FFLAGS="-O2 -fno-common"
#}

If you haven't already installed Darwin Ports, you can find easy instructions for doing so at the main Darwin Ports page.
Once Darwin Ports has been installed, in a terminal window and while online, type the following and hit return:

%  cd /opt/local/bin/portslocation/dports/udunits
%  sudo port install udunits  
Password: 

You will then be prompted for your root password, which you should enter. You may have to wait for a few minutes while the software is retrieved from the network and installed for you. Y ou should see something that looks similar to:

--->  Fetching udunits
--->  Verifying checksum for udunits
--->  Extracting udunits
--->  Configuring udunits
--->  Building udunits with target all

--->  Staging udunits into destroot

--->  Installing udunits

- Make sure that you do not close the terminal window while Darwin Ports is working. Once the software has been installed, you can find further information about using udunits with these commands:

%  man udunits
%  apropos udunits
%  which udunits
%  locate udunits

 Where to find more information: