Add update command

[twpayne]

chezmoi uses relies on the user's source version control system to share changes across machines. You then need to run chezmoi apply on each machine.

These commands should be merged into a single chezmoi update command that does the following:

1. Updates the source directory according to the user's VCS (e.g. git pull --rebase if the VCS is git).
2. Runs chezmoi apply.

This will allow a single chezmoi update on a machine to update that machine to the user's desired state.

[tralston]

@twpayne How would I do a pull without applying? Especially during testing, and adapting existing machines to the chezmoi system, I don't want to automatically overwrite everything. I'd like to:

1. chezmoi update (to get the latest changes from my repo)
2. Analyze it with chezmoi diff to maker sure I haven't missed something on my local system.

I tried using chezmoi update -a false and chezmoi update -a 0 but none of those will allow me to signal the update command to NOT apply right after. How can this be done?

[tralston]

I can do this by the following:

1. chezmoi cd
2. git pull
3. exit
4. chezmoi diff

It's a workaround, but still long-winded. I'd like to just run chezmoi update --no-apply && chezmoi diff or something similar.

[twpayne]

chezmoi apply --dry-run (or chezmoi apply -n) should do the trick.

[twpayne]

Sorry, what I wrote isn't quite right - the --dry-run will apply to git pull as well so it won't actually pull.

chezmoi source pull && chezmoi diff is what you want, I think.

[twpayne]

You asked a good question, I added it to the docs (it wasn't there before) in #391.