diff --git a/hardware/gpu/cuda-prime.nix b/hardware/gpu/cuda-prime.nix
index 6ca38fe..cf9f9b3 100644
--- a/hardware/gpu/cuda-prime.nix
+++ b/hardware/gpu/cuda-prime.nix
@@ -7,6 +7,7 @@
 
   hardware.nvidia.prime = {
     # (required) Bus IDs. You can find them using lspci, grepping for "3D" or "VGA"
+    #     lspci | grep -iE "(3D|VGA)"
     # intelBusId  = "PCI:0:2:0";
     # nvidiaBusId = "PCI:1:0:0";
 
diff --git a/justfile b/justfile
index 57fdf13..8b6e707 100644
--- a/justfile
+++ b/justfile
@@ -19,6 +19,9 @@ eval-vm $hostname=`just _a_host` $attrpath="system.build.toplevel.outPath" *args
 repl $hostname=`just _a_host`:
   NIX_NO_NOM=1 nixos-rebuild-ng --flake .#"$hostname" repl
 
+why-depends $hostname $attrpath:
+  nix why-depends .#nixosConfigurations."$hostname".config.system.build.toplevel .#nixosConfigurations."$hostname".pkgs."$attrpath"
+
 report hostname=`just _a_host`:
   nix eval .#nixosReports."{{hostname}}" --json --show-trace | yq . --yaml-output --width=999999 | bat --language yaml --style plain --paging never
 
diff --git a/profiles/base/ccache/default.nix b/profiles/base/ccache/default.nix
index 45a72dd..6cd767f 100644
--- a/profiles/base/ccache/default.nix
+++ b/profiles/base/ccache/default.nix
@@ -7,6 +7,7 @@
 
 # serge <3
 # TODO: distributed (s)ccache (with redis?)
+# TODO: garbage collect this
 
 {
   programs.ccache.enable = true;
diff --git a/profiles/base/nix.nix b/profiles/base/nix.nix
index 2433a28..5d7ce4f 100644
--- a/profiles/base/nix.nix
+++ b/profiles/base/nix.nix
@@ -14,12 +14,21 @@
     !include ${config.sops.secrets.nix-access-tokens-all.path}
   '';
 
+  # https://nix.dev/manual/nix/stable/command-ref/conf-file.html
+  # https://nix.dev/manual/nix/latest/command-ref/conf-file.html
+  # https://docs.lix.systems/manual/lix/stable/command-ref/conf-file.html
   nix.settings = {
+
+    # === behaviour
     experimental-features = [
       "nix-command"
       "flakes"
       # "pipe-operator" # not supported on lix 2.91
     ];
+    log-lines = 35;
+    # keep-going = true;
+
+    # === access
     #nix.settings.allowed-users = [ "@builders" ]; # TODO: this
     allowed-users = [
       # default is [ "*" ]
@@ -30,13 +39,20 @@
       "root"
       "@wheel"
     ];
+
+    # === eval and realization
     keep-derivations = true; # keep .drv in store, great with nix-diff
+    max-silent-time = 3600; # kill long-running silent builds
+
+    # === substitution
+    connect-timeout = 5; # timeout in seconds for binary caches
+    download-attempts = lib.mkDefault 2; # download attempts, in case a binary cache fails
+    # fallback = lib.mkDefault true; # fallback to building if a binary cache fails
+
+    # === store
+    #settings.keep-failed = true; # fills up $TMPDIR
     auto-optimise-store = true; # deduplicate with hardlinks, expensive. Alternative: nix-store --optimise
-    max-silent-time = 3600;
-    connect-timeout = 5; # seconds timeout for binary caches
-    #nix.settings.keep-failed = true; # fills up $TMPDIR
-    log-lines = 35;
-    min-free = 3 * 1024 * 1024 * 1024; # starts cg
+    min-free = 5 * 1024 * 1024 * 1024; # starts cg
     max-free = 20 * 1024 * 1024 * 1024; # condition to end gc triggered by min-free
 
     # should not be needed since https://github.com/NixOS/nixpkgs/pull/383052
@@ -53,8 +69,9 @@
         ];
   };
 
+  #nix.optimize.automatic = true; # periodic store optimization, alternative nix.settings.auto-optimise-store
+
   nix.gc = {
-    #nix.optimize.automatic = true; # periodic optimization
     automatic = true;
     dates = "weekly";
     options = lib.mkIf config.system.autoUpgrade.enable "--delete-older-than 15d";
diff --git a/profiles/known-hosts/default.nix b/profiles/known-hosts/default.nix
index 3b32a98..5d06585 100644
--- a/profiles/known-hosts/default.nix
+++ b/profiles/known-hosts/default.nix
@@ -161,12 +161,23 @@ in {
     description = "Which specialization this is, if any.";
   };
 
-
-
   config = {
     nix.settings.max-jobs =
       lib.mkIf ((thisHost.buildMachine.maxJobs or 0) > 0)
       (lib.mkDefault thisHost.buildMachine.maxJobs);
   };
 
+  # TODO:
+  # nix.buildMachines = [
+  #   {
+  #     protocol = null;
+  #     hostName = "localhost";
+  #     speedFactor = SOMETHING; // perhaps by looking up self in hosts.toml, perhaps by always preferring self, perhaps by always preferring remotes
+  #     maxJobs = config.nix.settings.SOMETHING;
+  #     system = config.nix.settings.SOMETHING;
+  #     supportedFeatures = config.nix.settings.SOMETHING;
+  #   }
+  # ];
+
+
 }
diff --git a/users/pbsds/home/profiles/nix.nix b/users/pbsds/home/profiles/nix.nix
index 4172e48..481302f 100644
--- a/users/pbsds/home/profiles/nix.nix
+++ b/users/pbsds/home/profiles/nix.nix
@@ -1,16 +1,16 @@
 { pkgs, ... }:
 let
   # why not just use functions normally? ctrl-alt-e is why!
-  _tmpfn_name = "_tmpfn_ex4aiNgu"; # pwgen ftw
-  mkArgsAlias = alias: ''${_tmpfn_name}() { unset -f ${_tmpfn_name}; ${alias}; }; ${_tmpfn_name}'';
+  _tmpfn_name_ = "_tmpfn_ex4aiNgu_"; # pwgen ftw
+  mkArgsAlias = alias: ''${_tmpfn_name_}() { unset -f ${_tmpfn_name_}; ${alias}; }; ${_tmpfn_name_}'';
 in
 {
 
   home.packages = with pkgs; [
-      /* flox */
-      /* devenv */
-      /* cachix */
-      /* nix-template */
+      # flox
+      # devenv
+      # cachix
+      # nix-template
       nix-output-monitor
       nix-du
       nix-tree
@@ -23,11 +23,11 @@ in
       unstable.nix-init
       unstable.deadnix
       unstable.statix
-      /* unstable.nixtract */
+      # unstable.nixtract
       unstable.nixfmt-rfc-style
       nurl
       # manix
-      #comma # collides with nix-index-database
+      # comma # collides with nix-index-database
       # devenv
       nix-fast-build
       nix-eval-jobs
diff --git a/users/pbsds/home/profiles/shell.nix b/users/pbsds/home/profiles/shell.nix
index 88c7551..124d468 100644
--- a/users/pbsds/home/profiles/shell.nix
+++ b/users/pbsds/home/profiles/shell.nix
@@ -3,8 +3,8 @@
 let
 
   # why not just use functions normally? ctrl-alt-e is why!
-  _tmpfn_name = "_tmpfn_ex4aiNgu"; # pwgen ftw
-  mkArgsAlias = alias: ''${_tmpfn_name}() { unset -f ${_tmpfn_name}; ${alias}; }; ${_tmpfn_name}'';
+  _tmpfn_name_ = "_tmpfn_ex4aiNgu_"; # pwgen ftw
+  mkArgsAlias = alias: ''${_tmpfn_name_}() { unset -f ${_tmpfn_name_}; ${alias}; }; ${_tmpfn_name_}'';
 
 in
 
@@ -136,7 +136,11 @@ in
   home.shellAliases.killall = "killall -v";
 
   # bin = "python -c 'import sys; sys.stdout.write(sys.stdin.read().strip())' | curl -is -X POST https://i.kuklef.se/upload -F content=@- -F expiration=10d | grep '^location:' | cut -d' ' -f2-";
-  home.shellAliases.bin = "${lib.getExe pkgs.netcat} termbin.com 9999";
+  home.shellAliases.termbin = "${lib.getExe pkgs.netcat} termbin.com 9999";
+
+  # https://github.com/nwtgck/piping-server
+  home.shellAliases.httppipe-in  = mkArgsAlias ''set -x; curl -T - https://ppng.io/"''${1:-ijoh1aeJiXail9gahlah}"''; # pwgen ftw
+  home.shellAliases.httppipe-out = mkArgsAlias ''set -x; curl https://ppng.io/"''${1:-ijoh1aeJiXail9gahlah}"''; # pwgen ftw
 
   # old alias, just learn to use ncdu lol
   home.shellAliases.dush = "du -shc * | sort -h";