I need to correct the perspective on a batch of nikon images shot at 14-18mm.
Is it possible to call the darktable perspective module from a script with an input file and get a fixed output file ?
If not possible with darktable are there any other OSS/linux solutions ?
Iain
Hi @lightaffaire and welcome!
I do not understand what you mean by “get a fixed output file” 
Apart from that, search for
https://duckduckgo.com/?q=darktable+cli&t=ffab&ia=web
See here, for instance: How to batch edit a collection of raw files in Darktable? - Photography Stack Exchange
Have fun!
Claes in Lund, Sweden
You can first make an xmp file for one image, then use darktable-cli to apply it to multiple files: darktable-cli man page - darktable - General Commands