Nix : Add nix_upgrade.

.config/bash/module/Nix.sh

@@ -28,7 +28,12 @@ function nix_unstable_small() {
 	nix-channel --add https://nixos.org/channels/nixos-unstable-small nixos
 }
 
-# Update system.
+# Update system (rebuild).
 function nix_update() {
+	nixos-rebuild switch
+}
+
+# Upgrade system.
+function nix_upgrade() {
 	nixos-rebuild switch --upgrade
 }

.doc/Bash.md

@@ -255,6 +255,10 @@ Command|Description
 Command|Description
 ---|---
 `nix_find <PACKAGE>`|Find Nix package path. 
+`nix_unstable`|Switch to Unstable branch. 
+`nix_unstable_small`|Switch to Small Unstable branch (for server). 
+`nix_update`|Update system (rebuild). 
+`nix_upgrade`|Upgrade system. 
 
 ## Notify.