Ubuntu: Convert psd files with imagemagick

gistfile1.txt

Source: http://superuser.com/questions/360434/any-way-to-save-all-psd-layers-separately

Imagemagick will by default convert a psd to multiple images:

convert file.psd file.png
will result in file-0.png, file-1.png etc for each layer. If you wanted a single image, use the flatten switch:

convert file.psd -flatten file.png
Imagemagick is available on osx, windows and linux. And iOS somehow.

convert file.psd[0] file.png can do best, but how can I using im4java like this?