Composer doesn\'t run correctly in Cygwin if you try to install it \"globally\".
Putting composer.phar into /usr/local/bin/composer, then trying to run it will result in
The easiest way is to install composer using the Windows installer from their website and then copy the two files 'composer' and 'composer.phar' from "C:\ProgramData\Composer" into a directory which is in the PATH variable. E.g. you could copy the files into the /bin/ directory of cygwin. Afterwards you can again uninstall the "Windows version" of composer.
Update! This is what I did: