chore: add restic secrets to .env

.env.example

@@ -0,0 +1,2 @@
+B2_ACCOUNT_ID=
+B2_ACCOUNT_KEY=

.envrc

@@ -1 +1,2 @@
 use flake
+dotenv

services/restic/home-pc.nix

@@ -1,7 +1,7 @@
 { config, lib, pkgs, ... }:
 
 # using the restic cli:
-# load credentials into shell via: export $(cat /path/to/credentials/file | xargs)
+# load credentials into shell by adding B2 secrets to .env (see .env.example).
 # useful commands for analysing restic stats [snapshot-id], restic diff [s1] [s2],
 
 with lib;

services/restic/rpi4.nix

@@ -1,7 +1,7 @@
 { config, lib, pkgs, ... }:
 
 # using the restic cli:
-# load credentials into shell via: export $(cat /path/to/credentials/file | xargs)
+# load credentials into shell by adding B2 secrets to .env (see .env.example).
 # useful commands for analysing restic stats [snapshot-id], restic diff [s1] [s2],
 
 with lib;