@@ -41,11 +41,11 @@ # The current default sdk for macOS fails to compile go projects, so we use a newer one for now.           # This has no effect on other platforms.
           callPackage = pkgs.darwin.apple_sdk_11_0.callPackage or pkgs.callPackage;
         in
-        {
+        rec {
           packages.default = callPackage ./nix/package.nix {
             inherit (gomod2nix.legacyPackages.${system}) buildGoApplication;
-            css = simple-css;
             inherit self;
+            css = simple-css;
           };
           devShells.default = callPackage ./nix/dev-shell.nix {
             pre-commit-check = {
@@ -61,6 +61,9 @@ import ./nix/pre-commit-checks.nix {                 inherit pkgs;
               }
             );
+            buildVersion = pkgs.testers.testVersion {
+              package = packages.default;
+            };
           };
         })
     );

@@ -12,6 +12,11 @@ "github.com/pelletier/go-toml/v2" 	"github.com/pkg/errors"
 )
 
+var (
+	CommitSHA string
+	ShortSHA  string
+)
+
 type URL struct {
 	*url.URL
 }

@@ -6,6 +6,7 @@ "fmt" 	"log/slog"
 	"net/http"
 	"os"
+	"searchix/internal/config"
 	"searchix/internal/file"
 	"strings"
 	"time"
@@ -28,6 +29,8 @@ req, err := http.NewRequestWithContext(ctx, "GET", url, http.NoBody) 	if err != nil {
 		return false, errors.WithMessagef(err, "could not create HTTP request for %s", url)
 	}
+
+	req.Header.Set("User-Agent", fmt.Sprintf("Searchix %s", config.ShortSHA))
 
 	if mtime != "" {
 		req.Header.Set("If-Modified-Since", mtime)

@@ -11,6 +11,7 @@ for h, v := range config.Web.Headers { 			w.Header().Add(h, v)
 		}
 		w.Header().Add("Content-Security-Policy", config.Web.ContentSecurityPolicy.String())
+		w.Header().Add("Server", "searchix/"+cfg.ShortSHA)
 
 		next.ServeHTTP(w, r)
 	})

@@ -35,6 +35,11 @@ } 
 const jsSnippet = template.HTML(livereload.JsSnippet) // #nosec G203
 
+type VersionInfo struct {
+	ShortSHA  string
+	CommitSHA string
+}
+
 type TemplateData struct {
 	Sources       map[string]*config.Source
 	Source        config.Source
@@ -42,6 +47,7 @@ Query         string 	Results       bool
 	SourceResult  *bleve.SearchResult
 	ExtraBodyHTML template.HTML
+	Version       VersionInfo
 }
 
 type ResultData[T options.NixOption] struct {
@@ -53,6 +59,11 @@ Prev           string 	Next           string
 }
 
+var versionInfo = &VersionInfo{
+	ShortSHA:  config.ShortSHA,
+	CommitSHA: config.CommitSHA,
+}
+
 func applyDevModeOverrides(config *config.Config) {
 	if len(config.Web.ContentSecurityPolicy.ScriptSrc) == 0 {
 		config.Web.ContentSecurityPolicy.ScriptSrc = config.Web.ContentSecurityPolicy.DefaultSrc
@@ -93,6 +104,7 @@ mux.HandleFunc("/{$}", func(w http.ResponseWriter, _ *http.Request) { 		indexData := TemplateData{
 			ExtraBodyHTML: config.Web.ExtraBodyHTML,
 			Sources:       config.Importer.Sources,
+			Version:       *versionInfo,
 		}
 		err := templates["index"].ExecuteTemplate(w, "index.gotmpl", indexData)
 		if err != nil {
@@ -140,6 +152,7 @@ TemplateData: TemplateData{ 					ExtraBodyHTML: config.Web.ExtraBodyHTML,
 					Source:        *source,
 					Sources:       config.Importer.Sources,
+					Version:       *versionInfo,
 				},
 				ResultsPerPage: search.ResultsPerPage,
 				Query:          qs,
@@ -200,6 +213,7 @@ ExtraBodyHTML: config.Web.ExtraBodyHTML, 				Sources:       config.Importer.Sources,
 				Source:        *source,
 				SourceResult:  sourceResult,
+				Version:       *versionInfo,
 			})
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusInternalServerError)

@@ -12,11 +12,12 @@ ) , buildGoApplication ? pkgs.buildGoApplication
 , css
 , self
+, testers
 }:
 let
   inherit (builtins) concatStringsSep match;
 
-  version = concatStringsSep "-" (match
+  version = "0-unstable-" + concatStringsSep "-" (match
     "([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2}).*"
     self.lastModifiedDate
   );
@@ -42,5 +43,16 @@ rm -f frontend/static/base.css     cp ${css} frontend/static/base.css
   '';
   tags = [ "embed" ];
+  ldflags = [
+    "-s"
+    "-w"
+    "-X"
+    "searchix/internal/config.CommitSHA=${self.rev or self.dirtyRev}"
+    "-X"
+    "searchix/internal/config.ShortSHA=${self.shortRev or self.dirtyShortRev}"
+    "-X"
+    "main.buildVersion=${version}"
+  ];
+
   modules = ../gomod2nix.toml;
 }

@@ -2,6 +2,7 @@ package main 
 import (
 	"flag"
+	"fmt"
 	"log"
 	"log/slog"
 	"os"
@@ -17,10 +18,13 @@ 	"github.com/pelletier/go-toml/v2"
 )
 
+var buildVersion string
+
 var (
 	configFile = flag.String("config", "config.toml", "config `file` to use")
 	liveReload = flag.Bool("live", false, "whether to enable live reloading (development)")
 	replace    = flag.Bool("replace", false, "whether to replace existing database, if it exists")
+	version    = flag.Bool("version", false, "print version information")
 )
 
 func nextOccurrenceOfLocalTime(t toml.LocalTime) time.Time {
@@ -45,6 +49,10 @@ } 
 func main() {
 	flag.Parse()
+	if *version {
+		fmt.Fprintln(os.Stderr, "searchix", buildVersion, config.CommitSHA)
+		os.Exit(0)
+	}
 
 	conf, err := config.GetConfig(*configFile)
 	if err != nil {