add:partial functionality

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"os/exec"
 
 	"filepass/internal/services"
 	"filepass/internal/tui"
@@ -11,6 +12,14 @@ import (
 )
 
 func main() {
+	if _, err := exec.LookPath("rsync"); err != nil {
+		fmt.Fprintln(os.Stderr, "error: rsync is required but was not found in PATH")
+		fmt.Fprintln(os.Stderr, "install it with your package manager, e.g.:")
+		fmt.Fprintln(os.Stderr, "  brew install rsync")
+		fmt.Fprintln(os.Stderr, "  apt install rsync")
+		os.Exit(1)
+	}
+
 	store, err := services.NewServicesStore()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "failed to initialise config:", err)