Print the mnemonic and the vault and unlocker listings to stdout (closes #138)

`secret generate mnemonic`, `secret vault list` and `secret unlocker list`,
in text and `--json` form, printed through cobra's `cmd.Println` and
`cmd.Printf`. Those write to stderr when no output writer is set, and the
binary sets none, so a pipe or `$(...)` got nothing. They now write to
`cmd.OutOrStdout()`, as `secret list` does, and so does "No versions found"
from `secret version list`. Status messages and the warning printed after
the mnemonic stay on stderr.

A new test runs the built binary and reads the stdout of `generate
mnemonic` and of both listings in both forms.

Model: opus-5-5

README.md

@@ -197,7 +197,8 @@ for confirmation, naming the version, the secret and its vault (see
 
 #### `secret generate mnemonic`
 
-Generates a cryptographically secure BIP39 mnemonic phrase.
+Generates a cryptographically secure BIP39 mnemonic phrase and prints it to
+stdout. The warning to keep it safe goes to stderr.
 
 #### `secret generate secret <name> [--length=16] [--type=base58] [--force]`
 

TODO.md

@@ -18,6 +18,14 @@ https://git.eeqj.de/sneak/secret/milestone/12
 
 # Completed Steps
 
+- 2026-10-14: `secret generate mnemonic`, `secret vault list` and
+  `secret unlocker list` print their output to stdout, as `secret list` does, so
+  it can be piped or captured (https://git.eeqj.de/sneak/secret/issues/138).
+  They printed with cobra's `cmd.Println` and `cmd.Printf`, which write to
+  stderr when no output writer is set, so `secret vault list --json | jq`
+  received nothing. "No versions found" from `secret version list` moved to
+  stdout too. Messages such as "Created vault", and the warning after the
+  mnemonic, stay on stderr.
 - 2026-10-14: Removing the current unlocker no longer leaves the vault unable to
   open through the unlockers it still has
   (https://git.eeqj.de/sneak/secret/issues/137). `current-unlocker` went on

internal/cli/generate.go

@@ -103,7 +103,7 @@ func (cli *Instance) GenerateMnemonic(cmd *cobra.Command) error {
 	}
 
 	// Output mnemonic to stdout
-	cmd.Println(mnemonic)
+	_, _ = fmt.Fprintln(cmd.OutOrStdout(), mnemonic)
 
 	// Output helpful information to stderr
 	fmt.Fprintln(os.Stderr, "")

internal/cli/stdout_stderr_test.go

@@ -2,6 +2,7 @@ package cli_test
 
 import (
 	"bytes"
+	"encoding/json"
 	"os/exec"
 	"path/filepath"
 	"strings"
@@ -9,6 +10,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/secret/internal/bip39"
 	"sneak.berlin/go/secret/internal/secret"
 )
 
@@ -90,3 +92,66 @@ func TestGetCommandOutputsToStdout(t *testing.T) {
 	// Nothing should be in stderr
 	assert.Empty(t, stderr.String(), "stderr should be empty")
 }
+
+// TestMnemonicAndListingsOutputToStdout tests that 'secret generate
+// mnemonic', 'secret vault list' and 'secret unlocker list' print their
+// output to stdout, so that it can be piped
+func TestMnemonicAndListingsOutputToStdout(t *testing.T) {
+	t.Parallel()
+
+	tempDir := t.TempDir()
+	secretPath := secretBinaryPath(t)
+
+	// run runs the secret binary and returns what it wrote to stdout and to
+	// stderr
+	run := func(args ...string) (string, string) {
+		//nolint:gosec // G204: test executes the freshly built secret binary
+		cmd := exec.CommandContext(t.Context(), secretPath, args...)
+		cmd.Env = []string{
+			secret.EnvStateDir + "=" + tempDir,
+			secret.EnvMnemonic + "=" + testMnemonic,
+			secret.EnvUnlockPassphrase + "=test-passphrase",
+			"PATH=/usr/bin:/bin",
+		}
+
+		var stdout, stderr bytes.Buffer
+
+		cmd.Stdout = &stdout
+		cmd.Stderr = &stderr
+
+		err := cmd.Run()
+		require.NoError(t, err, "%v should succeed: %s", args, stderr.String())
+
+		return stdout.String(), stderr.String()
+	}
+
+	stdout, stderr := run("generate", "mnemonic")
+	assert.True(t, bip39.IsMnemonicValid(strings.TrimSpace(stdout)),
+		"stdout should hold the mnemonic, not %q", stdout)
+	assert.Contains(t, stderr, "Save this mnemonic phrase securely",
+		"the warning should be on stderr")
+
+	run("init")
+
+	stdout, _ = run("vault", "list", "--json")
+
+	var vaults map[string]any
+
+	require.NoError(t, json.Unmarshal([]byte(stdout), &vaults),
+		"stdout should hold the vaults as JSON, not %q", stdout)
+	assert.Equal(t, "default", vaults["currentVault"])
+
+	stdout, _ = run("unlocker", "list", "--json")
+
+	var unlockers map[string]any
+
+	require.NoError(t, json.Unmarshal([]byte(stdout), &unlockers),
+		"stdout should hold the unlockers as JSON, not %q", stdout)
+	assert.Len(t, unlockers["unlockers"], 1)
+
+	stdout, _ = run("vault", "list")
+	assert.Contains(t, stdout, "default (current)")
+
+	stdout, _ = run("unlocker", "list")
+	assert.Contains(t, stdout, "Total: 1 unlocker(s)")
+}

internal/cli/unlockers.go

@@ -326,22 +326,25 @@ func (cli *Instance) printUnlockersJSON(
 		return fmt.Errorf("failed to marshal JSON: %w", err)
 	}
 
-	cli.cmd.Println(string(jsonBytes))
+	_, _ = fmt.Fprintln(cli.cmd.OutOrStdout(), string(jsonBytes))
 
 	return nil
 }
 
 // printUnlockersTable prints unlockers in a formatted table
 func (cli *Instance) printUnlockersTable(unlockers []UnlockerInfo) error {
+	out := cli.cmd.OutOrStdout()
+
 	if len(unlockers) == 0 {
-		cli.cmd.Println("No unlockers found in current vault.")
+		_, _ = fmt.Fprintln(out, "No unlockers found in current vault.")
-		cli.cmd.Println("Run 'secret unlocker add passphrase' to create one.")
+		_, _ = fmt.Fprintln(out, "Run 'secret unlocker add passphrase' to create one.")
 
 		return nil
 	}
 
-	cli.cmd.Printf("  %-40s %-12s %-20s %s\n", "UNLOCKER ID", "TYPE", "CREATED", "FLAGS")
+	_, _ = fmt.Fprintf(out, "  %-40s %-12s %-20s %s\n",
-	cli.cmd.Printf("  %-40s %-12s %-20s %s\n",
+		"UNLOCKER ID", "TYPE", "CREATED", "FLAGS")
+	_, _ = fmt.Fprintf(out, "  %-40s %-12s %-20s %s\n",
 		strings.Repeat("-", unlockerIDWidth), strings.Repeat("-", unlockerTypeWidth),
 		strings.Repeat("-", unlockerDateWidth), strings.Repeat("-", unlockerFlagsWidth))
 
@@ -356,7 +359,7 @@ func (cli *Instance) printUnlockersTable(unlockers []UnlockerInfo) error {
 			prefix = "* "
 		}
 
-		cli.cmd.Printf("%s%-40s %-12s %-20s %s\n",
+		_, _ = fmt.Fprintf(out, "%s%-40s %-12s %-20s %s\n",
 			prefix,
 			unlocker.ID,
 			unlocker.Type,
@@ -364,7 +367,7 @@ func (cli *Instance) printUnlockersTable(unlockers []UnlockerInfo) error {
 			flags)
 	}
 
-	cli.cmd.Printf("\nTotal: %d unlocker(s)\n", len(unlockers))
+	_, _ = fmt.Fprintf(out, "\nTotal: %d unlocker(s)\n", len(unlockers))
 
 	return nil
 }

internal/cli/vault.go

@@ -186,6 +186,8 @@ func (cli *Instance) ListVaults(cmd *cobra.Command, jsonOutput bool) error {
 		return err
 	}
 
+	out := cmd.OutOrStdout()
+
 	if jsonOutput { //nolint:nestif // Separate JSON and text output formatting logic
 		// Get current vault name for context
 		currentVault := ""
@@ -205,13 +207,13 @@ func (cli *Instance) ListVaults(cmd *cobra.Command, jsonOutput bool) error {
 			return err
 		}
 
-		cmd.Println(string(jsonBytes))
+		_, _ = fmt.Fprintln(out, string(jsonBytes))
 	} else {
 		// Text output
-		cmd.Println("Available vaults:")
+		_, _ = fmt.Fprintln(out, "Available vaults:")
 
 		if len(vaults) == 0 {
-			cmd.Println("  (none)")
+			_, _ = fmt.Fprintln(out, "  (none)")
 		} else {
 			// Try to get current vault for marking
 			currentVault := ""
@@ -223,9 +225,9 @@ func (cli *Instance) ListVaults(cmd *cobra.Command, jsonOutput bool) error {
 
 			for _, vaultName := range vaults {
 				if vaultName == currentVault {
-					cmd.Printf("  %s (current)\n", vaultName)
+					_, _ = fmt.Fprintf(out, "  %s (current)\n", vaultName)
 				} else {
-					cmd.Printf("  %s\n", vaultName)
+					_, _ = fmt.Fprintf(out, "  %s\n", vaultName)
 				}
 			}
 		}

internal/cli/version.go

@@ -167,7 +167,7 @@ func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 	}
 
 	if len(versions) == 0 {
-		cmd.Println("No versions found")
+		_, _ = fmt.Fprintln(cmd.OutOrStdout(), "No versions found")
 
 		return nil
 	}