feat: add alias file generation and management for shell hooks

- **Aliases**: Generate shell alias files (`aliases.sh` for bash/zsh, `netssh.fish` for fish) from cached hosts. Regenerate on each shell startup and cache refresh to keep aliases updated.
- **Hooks**: Extend shell hook functionality to include alias file support. Install and uninstall commands updated for bash, zsh, and fish.
- **Tests**: Add unit tests to verify alias file generation, path resolution, and idempotent hook installation.
- **Docs**: Update README with instructions for alias file usage, installation, and relation to hooks.

cmd/netssh/main.go

@@ -521,6 +521,11 @@ func cacheRefreshCmd() *cobra.Command {
 			if err := c.SetRefreshed(); err != nil {
 				fmt.Fprintf(os.Stderr, "warning: could not update refresh timestamp: %v\n", err)
 			}
+			if aliasEntries := buildAliasEntries(c, *cfg); len(aliasEntries) > 0 {
+				if err := hook.WriteAliasFiles(aliasEntries); err != nil {
+					fmt.Fprintf(os.Stderr, "warning: could not write alias files: %v\n", err)
+				}
+			}
 			fmt.Printf("%d entries written to cache.\n", len(entries))
 			return nil
 		},
@@ -530,6 +535,27 @@ func cacheRefreshCmd() *cobra.Command {
 	return cmd
 }
 
+// buildAliasEntries computes the sorted, deduplicated alias list from the cache.
+func buildAliasEntries(c *cache.Cache, cfg config.Config) []hook.AliasEntry {
+	all := c.All()
+	sort.Slice(all, func(i, j int) bool { return all[i].Name < all[j].Name })
+
+	seen := make(map[string]string)
+	var out []hook.AliasEntry
+	for _, e := range all {
+		name := shortcuts.AliasName(e.Name, cfg.Shortcuts)
+		if name == "" {
+			continue
+		}
+		if _, dup := seen[name]; dup {
+			continue
+		}
+		seen[name] = e.Name
+		out = append(out, hook.AliasEntry{Name: name, Host: e.Name})
+	}
+	return out
+}
+
 func aliasCmd() *cobra.Command {
 	var shell string
 	cmd := &cobra.Command{
@@ -558,46 +584,23 @@ Or use in a script:
 				shell = filepath.Base(os.Getenv("SHELL"))
 			}
 
-			entries := c.All()
-			sort.Slice(entries, func(i, j int) bool {
-				return entries[i].Name < entries[j].Name
-			})
-
-			// Deduplicate: first host wins when two normalize to the same alias.
-			seen := make(map[string]string) // alias name → canonical name
-			var lines []string
-			for _, e := range entries {
-				aliasName := shortcuts.AliasName(e.Name, cfg.Shortcuts)
-				if aliasName == "" {
-					continue
-				}
-				if prev, exists := seen[aliasName]; exists {
-					fmt.Fprintf(os.Stderr, "netssh: alias %q conflict: %s and %s — skipping %s\n", aliasName, prev, e.Name, e.Name)
-					continue
-				}
-				seen[aliasName] = e.Name
-
-				switch shell {
-				case "fish":
-					lines = append(lines, fmt.Sprintf("alias %s 'netssh %s'", aliasName, e.Name))
-				default:
-					lines = append(lines, fmt.Sprintf("alias %s='netssh %s'", aliasName, e.Name))
-				}
-			}
-
-			if len(lines) == 0 {
+			entries := buildAliasEntries(c, *cfg)
+			if len(entries) == 0 {
 				fmt.Fprintln(os.Stderr, "netssh: cache is empty — run 'netssh cache refresh' first")
 				return nil
 			}
 
 			switch shell {
 			case "fish":
-				fmt.Printf("# netssh aliases (%d hosts) — source with: netssh alias --shell fish | source\n", len(lines))
+				fmt.Printf("# netssh aliases (%d hosts) — source with: netssh alias --shell fish | source\n", len(entries))
+				for _, e := range entries {
+					fmt.Printf("alias %s 'netssh %s'\n", e.Name, e.Host)
+				}
 			default:
-				fmt.Printf("# netssh aliases (%d hosts) — source with: eval \"$(netssh alias)\"\n", len(lines))
-			}
-			for _, l := range lines {
-				fmt.Println(l)
+				fmt.Printf("# netssh aliases (%d hosts) — source with: eval \"$(netssh alias)\"\n", len(entries))
+				for _, e := range entries {
+					fmt.Printf("alias %s='netssh %s'\n", e.Name, e.Host)
+				}
 			}
 			return nil
 		},
@@ -606,12 +609,12 @@ Or use in a script:
 	return cmd
 }
 
-// shellInitCmd is called at shell startup to trigger a background cache refresh when stale.
-// It is intentionally silent — no output on success so it never disrupts shell startup.
+// shellInitCmd is called at shell startup to update alias files and trigger a
+// background cache refresh when stale. Intentionally silent — never disrupts the prompt.
 func shellInitCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:    "shell-init",
-		Short:  "Trigger a background cache refresh if stale (add to shell profile via 'hook install')",
+		Short:  "Regenerate alias files and trigger a background cache refresh if stale",
 		Hidden: true,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			cfg, err := config.Load()
@@ -619,6 +622,14 @@ func shellInitCmd() *cobra.Command {
 				return nil
 			}
 			c := cache.New(cfg.Cache.Path, cfg.Cache.TTL)
+			_ = c.Load()
+
+			// Regenerate alias files from the current cache every shell start
+			// so aliases are always up-to-date even before a refresh completes.
+			if entries := buildAliasEntries(c, *cfg); len(entries) > 0 {
+				_ = hook.WriteAliasFiles(entries)
+			}
+
 			maybeBackgroundRefresh(cfg, c)
 			return nil
 		},
@@ -652,15 +663,41 @@ After installation, reload your profile or open a new shell.`,
 			if err != nil {
 				return err
 			}
+
 			installed, err := hook.Install(profile)
 			if err != nil {
 				return err
 			}
+			// For bash/zsh: also add the source line so aliases are loaded on startup.
+			// Fish uses conf.d auto-sourcing — no explicit source line needed.
+			if shell != "fish" {
+				if _, err := hook.InstallAliasesSource(profile); err != nil {
+					return err
+				}
+			}
+
 			if !installed {
 				fmt.Printf("Hook already installed in %s\n", profile)
-				return nil
+			} else {
+				fmt.Printf("Hook installed → %s\n%s\n", profile, hook.ReloadNote(profile))
+			}
+
+			// Generate the aliases file immediately so it is ready on the next shell start.
+			cfg, cfgErr := config.Load()
+			if cfgErr == nil && cfg.NetBox.URL != "" {
+				c := cache.New(cfg.Cache.Path, cfg.Cache.TTL)
+				if _ = c.Load(); true {
+					if entries := buildAliasEntries(c, *cfg); len(entries) > 0 {
+						if err := hook.WriteAliasFiles(entries); err != nil {
+							fmt.Fprintf(os.Stderr, "warning: could not write alias files: %v\n", err)
+						} else {
+							fmt.Printf("%d aliases written to %s\n", len(entries), hook.AliasesPath())
+						}
+					} else {
+						fmt.Println("Cache is empty — run 'netssh cache refresh' to populate aliases.")
+					}
+				}
 			}
-			fmt.Printf("Hook installed → %s\n%s\n", profile, hook.ReloadNote(profile))
 			return nil
 		},
 	}