fish: add nix_upgrade function

fish/functions/nix_upgrade.fish

@@ -0,0 +1,27 @@
+function nix_upgrade --description "Upgrade nix packages"
+    # Step 1: Update Nixpkgs channel
+    nix-channel --update
+
+    # Step 2: Determine changes, if any
+    set --local nix_pkgs_filepath "$HOME/.config/nix/packages.nix"
+    set --local nix_pkgs_available (nix-env -qacf "$nix_pkgs_filepath" | grep -v ' = ' | string collect)
+    set --local nix_pkgs_installed (nix-env -qcf  "$nix_pkgs_filepath" | grep -v ' = ' | string collect)
+
+    if test -z "$nix_pkgs_available" && test -z "$nix_pkgs_installed"
+        echo "All packages up-to-date."
+        return 0
+    end
+
+    set --local nix_pkgs_upd (echo $nix_pkgs_available | grep -v ' - \? ' | awk '{print $1}')
+    set --local nix_pkgs_add (echo $nix_pkgs_available | grep ' - \? ' | awk '{print $1}')
+    set --local nix_pkgs_rem (echo $nix_pkgs_installed | grep ' - \? ' | awk '{print $1}')
+
+    test -z "$nix_pkgs_add" || echo "Added packages: $nix_pkgs_add"
+    test -z "$nix_pkgs_upd" || echo "Outdated packages: $nix_pkgs_upd"
+    test -z "$nix_pkgs_rem" || echo "Removed packages: $nix_pkgs_rem"
+
+    # Step 3: Confirm changes
+    if confirm
+        nix-env -irf "$nix_pkgs_filepath"
+    end
+end

fish/functions/npm_upgrade.fish

@@ -1,7 +1,7 @@
 function npm_upgrade --description "Upgrade npm packages"
     set --local npm_pkgs_outdated (npm outdated -g | awk 'NR > 1 {print $1}')
 
-    if test (count $npm_pkgs_outdated) = 0
+    if test (count $npm_pkgs_outdated) -eq 0
         echo "All packages up-to-date."
     else
         echo "Outdated packages: $npm_pkgs_outdated"

fish/functions/pip_upgrade.fish

@@ -1,7 +1,7 @@
 function pip_upgrade --description "Upgrade python packages"
     set --local py_pkgs_outdated (python3 -m pip list --outdated | awk 'NR > 2 {print $1}')
 
-    if test (count $py_pkgs_outdated) = 0
+    if test (count $py_pkgs_outdated) -eq 0
         echo "All packages up-to-date."
     else
         echo "Outdated packages: $py_pkgs_outdated"

install/install-nix-packages.sh

@@ -6,7 +6,7 @@ ROOTDIR=$(cd "$(dirname "$0")/.." && pwd)
 NIX_ENV="$HOME/.nix-profile/bin/nix-env"
 
 if [ -x "$NIX_ENV" ]; then
-	"$NIX_ENV" --install --remove-all --file "$ROOTDIR/install/packages.nix"
+	"$NIX_ENV" --install --remove-all --file "$ROOTDIR/nix/packages.nix"
 else
 	echo "Cannot install Nix packages! $NIX_ENV is not executable."
 fi

install/install-symlinks.sh

@@ -19,6 +19,7 @@ mkdir -p "$HOME/.config"
 backup_existing "$HOME/.bashrc"
 backup_existing "$HOME/.config/fish"
 backup_existing "$HOME/.config/kitty"
+backup_existing "$HOME/.config/nix"
 backup_existing "$HOME/.config/nvim"
 backup_existing "$HOME/.config/git"
 
@@ -26,6 +27,7 @@ backup_existing "$HOME/.config/git"
 ln -fsv "$ROOTDIR/bash/.bashrc" "$HOME/.bashrc" # Bash does not support XDG config
 ln -fsv "$ROOTDIR/fish"         "$HOME/.config"
 ln -fsv "$ROOTDIR/kitty"        "$HOME/.config"
+ln -fsv "$ROOTDIR/nix"          "$HOME/.config"
 ln -fsv "$ROOTDIR/nvim"         "$HOME/.config"
 ln -fsv "$ROOTDIR/git"          "$HOME/.config"
 

nix/packages.nix

@@ -1,6 +1,6 @@
 # Moving toward a more declarative user environment...
 # This "Nix expression" describes the set of packages I want in my user environment.
-# Whenever it changes, run `nix-env -irf /path/to/packages.nix` to reinstall the environment.
+# Whenever it changes, run `nix-env -irf ~/.config/nix/packages.nix` to reinstall the environment.
 
 with import <nixpkgs> {}; [
     bat