diff --git a/Justfile b/Justfile
index 60d9e891..d639b520 100644
--- a/Justfile
+++ b/Justfile
@@ -45,6 +45,7 @@ repl:
   nix repl -f flake:nixpkgs
 
 # remove all generations older than 7 days
+# on darwin, you may need to switch to root user to run this command
 [group('nix')]
 clean:
   sudo nix profile wipe-history --profile /nix/var/nix/profiles/system  --older-than 7d
@@ -53,8 +54,14 @@ clean:
 [group('nix')]
 gc:
   # garbage collect all unused nix store entries
+  # NOTE: it's a system-wide garbage collection, but it seems won't affect home-manager's gcroot on darwin
   sudo nix-collect-garbage --delete-old
 
+[group('nix')]
+gc-home:
+  # garbage collect all unused nix store entries(for the user - home-manager)
+  nix-collect-garbage --delete-old
+
 # Enter a shell session which has all the necessary tools for this flake
 [linux]
 [group('nix')]
@@ -72,6 +79,11 @@ fmt:
   # format the nix files in this repo
   nix fmt
 
+# Show all the auto gc roots in the nix store
+[group('nix')]
+gcroot:
+  ls -al /nix/var/nix/gcroots/auto/
+
 ############################################################################
 #
 #  NixOS Desktop related commands