nix: add channel configuration and rework update process

Justfile

@@ -1,33 +1,45 @@
+_usage:
+	just -l
+
 _device action dir +moreargs="":
 	#!/usr/bin/env bash
-	set -e
-	sudo $(nix-build --no-link --show-trace $(dirname {{dir}})/default.nix -A {{action}} --argstr dir {{dir}} {{moreargs}} )
+	set -ex
+	sudo $(set -x; nix-build --no-link --show-trace $(dirname {{dir}})/default.nix -A {{action}} --argstr dir {{dir}} {{moreargs}})
 
+_rebuild-device dir rebuildarg="dry-activate" +moreargs="":
+	just -v _device rebuild {{dir}} --argstr rebuildarg {{rebuildarg}} {{moreargs}}
 
-_rebuild-device dir rebuildarg="dry-activate":
-	just -v _device rebuild {{dir}} --argstr rebuildarg {{rebuildarg}}
 
 # Rebulid this device's NixOS
 rebuild-this-device rebuildarg="dry-activate":
 	just -v _rebuild-device nix/os/devices/$(hostname -s) {{rebuildarg}}
 
+# This could be used to inject another channel
+# --argstr moreargs "\'-I nixos-unstable=https://nixos.org/channels/nixos-unstable/nixexprs.tar.xz\'"
+
+
 # Update nix-channels and switch to updated NixOS and home environments
 update-this-device:
 	#!/usr/bin/env bash
+	export SYSUPDATE_LOG=.$(hostname -s)_sysupdate.log
+	export HOMEUPDATE_LOG=.$(hostname -s)_homeupdate.log
+
 	echo Updating system channels...
-	sudo nix-channel --update > .$(hostname -s)_sysupdate.log 2>&1
+	sudo nix-channel --update > ${SYSUPDATE_LOG} 2>&1
 	echo Updating system...
-	if just -v rebuild-this-device >> .$(hostname -s)_sysupdate.log 2>&1 ; then 
+	if just -v rebuild-this-device switch >> ${SYSUPDATE_LOG} 2>&1 ; then
 		echo System update successful
 	else
-		System update failed
+		cat ${SYSUPDATE_LOG}
+		echo System update failed
 	fi
 
 	if type home-manager > /dev/null 2>&1; then
 		echo Updating home...
-		if home-manager -v switch > .$(hostname -s)_homeupdate.log 2>&1 ; then 
+		if home-manager -v switch > ${HOMEUPDATE_LOG} 2>&1 ; then
 			echo Home update successful
-		else 
+		else
+			cat ${HOMEUPDATE_LOG}
 			echo Home update failed
 		fi
 	fi