Update…
It seems I’m using the --command argument properly, as I can set the color_scheme successfully this way:
subl --command 'set_setting {"setting": "color_scheme", "value": "Packages/Color Scheme - Default/Solarized (Dark).tmTheme"}'
However, I’ve found two commands, both “insert” and “insert_snippet”, neither of which work when used in the following way (the file is opened, but no string is present in the newly opened sublime tab):
subl --command 'insert {"string" : "woohoo"}' ~/Desktop/yay.md
subl --command 'insert_snippet {"contents" : "woohoo"}' ~/Desktop/yay.md
Commands found at: http://docs.sublimetext.info/en/latest/reference/commands.html
Any insight very much appreciated!