Add get-tags and count-tags scripts

Add `get-tags` and `count-tags` scripts to get and count Git tags within
a repository, including the ability to filter tags - e.g. only get or
count tags that begin with a certain date.

home-manager/opdavies/PW05CH3L.nix

@@ -38,7 +38,9 @@
   };
 
   home.packages = with pkgs; [
+    count-tags
     create-script
+    get-tags
     tag-release
     time-until
     update-all-git-repos

home-manager/opdavies/t480.nix

@@ -99,8 +99,10 @@
   home.packages = with pkgs; [
     backup-websites
     build-glove80
+    count-tags
     create-script
     displayselect
+    get-tags
     qrencode
     mounter
     move-firefox-screenshots

packages/count-tags.nix

@@ -0,0 +1,14 @@
+{ pkgs }:
+
+pkgs.writeShellApplication {
+  name = "count-tags";
+
+  runtimeInputs = with pkgs; [
+    coreutils
+    get-tags
+  ];
+
+  text = ''
+    get-tags "''${1:-}" | wc -l
+  '';
+}

packages/default.nix

@@ -9,9 +9,11 @@ in
   _timer = callPackage ./_timer.nix { };
   backup-websites = callPackage ./backup-websites.nix { };
   build-glove80 = callPackage ./build-glove80.nix { };
+  count-tags = callPackage ./count-tags.nix { };
   create-script = callPackage ./create-script.nix { };
   dev-commit = callPackage ./dev-commit.nix { };
   displayselect = callPackage ./displayselect { };
+  get-tags = callPackage ./get-tags.nix { };
   git-graph = callPackage ./git-graph.nix { };
   mounter = callPackage ./mounter.nix { };
   move-firefox-screenshots = callPackage ./move-firefox-screenshots.nix { };

packages/get-tags.nix

@@ -0,0 +1,19 @@
+{ pkgs }:
+
+pkgs.writeShellApplication {
+  name = "get-tags";
+
+  runtimeInputs = with pkgs; [
+    git
+    unixtools.column
+  ];
+
+  text = ''
+    if [[ "$#" -gt 0 ]]; then
+      git tag | grep "$*"
+      exit 0
+    fi
+
+    git tag
+  '';
+}