(constph)rustenburg@jak:~$ conda create -n test python=3.5
Fetching package metadata: ....
Solving package specifications: ..........
Package plan for installation in environment /home/rustenburg/miniconda2/envs/test:
The following NEW packages will be INSTALLED:
    openssl:    1.0.2d-0      defaults
    pip:        7.1.2-py35_0  defaults
    python:     3.5.1-0       defaults
    readline:   6.2-2         defaults
    setuptools: 18.5-py35_0   defaults
    sqlite:     3.8.4.1-1     defaults
    tk:         8.5.18-0      defaults
    wheel:      0.26.0-py35_1 defaults
    xz:         5.0.5-0       defaults
    zlib:       1.2.8-0       defaults
Proceed ([y]/n)? y
Linking packages ...
[      COMPLETE      ]|###################################################| 100%
#
# To activate this environment, use:
# $ source activate test
#
# To deactivate this environment, use:
# $ source deactivate
#
(constph)rustenburg@jak:~$ source activate test
discarding /home/rustenburg/miniconda2/envs/constph/bin from PATH
prepending /home/rustenburg/miniconda2/envs/test/bin to PATH
(test)rustenburg@jak:~$ conda install -c omnia openmm-dev
Fetching package metadata: ......
Solving package specifications: .............
Package plan for installation in environment /home/rustenburg/miniconda2/envs/test:
The following NEW packages will be INSTALLED:
    fftw3f:     3.3.4-2           omnia
    openmm-dev: 7.0.0.dev0-py35_0 omnia
Proceed ([y]/n)? y
Linking packages ...
[      COMPLETE      ]|###################################################| 100%
(test)rustenburg@jak:~$ conda env export > environment.yml
(test)rustenburg@jak:~$ cat environment.yml 
name: test
dependencies:
- fftw3f=3.3.4=2
- openmm-dev=7.0.0.dev0=py35_0
- openssl=1.0.2d=0
- pip=7.1.2=py35_0
- python=3.5.1=0
- readline=6.2=2
- setuptools=18.5=py35_0
- sqlite=3.8.4.1=1
- tk=8.5.18=0
- wheel=0.26.0=py35_1
- xz=5.0.5=0
- zlib=1.2.8=0
- pip:
  - openmm==7.0.0