Have a look at install.sh, it contains all the steps to install elm-new in any Linux or OS X machine.
Just open a terminal and run it:
curl https://raw.githubusercontent.com/simonewebdesign/elm-new/master/install.sh | sh
If it didn't work for you, please let me know by opening a new issue!
elm-new would normally install itself in /usr/local/bin/elm-new. If you want to install to a different path, for example say /tmp/elm, you can do:
make DESTDIR=/tmp/elm install
You would then find elm-new under /tmp/elm/usr/local/bin.
It is also possible to customize the prefix (/usr/local by default). For example:
make PREFIX=~/opt install
The above would install elm-new under ~/opt/bin.
In any case, if you wish to simply run elm-new without specifying the full path, you need to add the bin folder to $PATH. For example, if you're using bash:
echo 'PATH=~/opt/bin:$PATH' >> ~/.bashrc
. ~/.bashrc
You don't need to clone or download this repo. Just open cmd.exe and run:
powershell -Command "(New-Object Net.WebClient).DownloadFile('https://raw.githubusercontent.com/simonewebdesign/elm-new/master/install.bat', '%temp%\install.bat')"
%temp%\install.bat
It will install the tool under C:\Tools\elm-new. If you want to just call the tool without specifying the full path, you need to add that path in your PATH environment variable: here's a guide.
The tool will also just work on MinGW; it can be installed normally as described in the README, or from source (see above).
You should be able to install it on Cygwin too if you have make. Here's how to get make.
If you're on Windows 10, whether you're using PowerShell or not, I'd highly recommend upgrading to the Anniversary Update: see this page.