I use nano for git commit messages. Short summary (<=50 chars) plus a new line before the description is relatively straightforward to stick to. However, when it comes to wrapping at 72 chars in the description body I just go off what seems to look right, making for inconsistent logs.
In Vagrantfiles I've seen this sort of thing to tell the editor what to do for vi/vim:
# -*- mode: ruby -*-
# vi: set ft=ruby :
Is there something like that for nano, and a template somewhere for git commit, that means I can ensure that nano would be set up for the correct line wrapping when in the context of a git commit message?
Nano supports the passing of command line arguments when starting it.
This can be leveraged as part of the git editor config setting.
git config --global core.editor "nano -r 72"
Or:
export GIT_EDITOR='nano -r 72'