Add param --template about geany HOT 1 OPEN

Its not impossible (at first glance) but there are a few issues.

1. there isn't a simple "create file from template" function, its a menu callback that gets the template from the menu not a parameter
2. the relationship between command line options is already pretty complex to make geany seem to mostly "just work", but this is likely to add more
3. it should not open in a new instance, this causes shared config problems, new instances should only be run with differing configs (-c)
4. to open in the original instance the protocol to communicate between the instances needs to be extended to support templates
5. how do you specify which template? and what to do it that doesn't exist?

None of that is impossible or "difficult" depending on your C programming skills.

from geany.