This one has baffled me – I'm actually trying to make a Thunar custom action to copy the selected file into the same directory appending a number before the extension, e.g.
cp file.ext file_1.ext
Some commands seem to do this automatically like the
mogrify -format (except obviously the extension changes).
For example I'd like to copy an image file so that I can
mogrify -resize the copy (which will be overwritten).