diff --git a/cmd/help/main.go b/cmd/help/main.go
index 7c89b31..318aa13 100644
--- a/cmd/help/main.go
+++ b/cmd/help/main.go
@@ -1,10 +1,12 @@
 package main
 
 import (
+	"bytes"
 	"database/sql"
 	"errors"
 	"fmt"
 	"os"
+	"os/exec"
 	"strconv"
 	"strings"
 
@@ -16,7 +18,7 @@ import (
 	"github.com/mattn/go-tty"
 )
 
-// TODO consider local-only help command for renaming and adding emails to account
+// TODO consider local-only help command for renaming, email mgmt, deleting account
 
 // TODO put colorscheme, prompting stuff into own packages for use in the other commands. would be good to get off of survey.
 
@@ -262,9 +264,27 @@ func redeemCode(db *sql.DB, cs colorScheme, p *Prompter) error {
 		return nil
 	}
 
-	// TODO need to create a new helper: appendkeyfile and use sudoers to allow help to call it. also need to add help user and add it to /etc/ssh/sshd_config
+	cmd := exec.Command("sudo", "--user", user.Username, "/town/bin/appendkeyfile", user.Username)
+	cmd.Stdin = bytes.NewBufferString(key)
+	stdoutBuff := bytes.NewBuffer([]byte{})
+	cmd.Stdout = stdoutBuff
+	if err = cmd.Run(); err != nil {
+		// TODO log error
+		//return fmt.Errorf("appendkeyfile failed with '%s': %w", string(stdoutBuff.Bytes()), err)
+		return errors.New("adding to keys file failed")
+	}
+
+	// TODO add help user
+	// TODO update sshd_config
+	// TODO update sudoers
+	// TODO compile appendkeyfile and add to /town/bin/
+
+	err = code.MarkUsed(db)
+	if err != nil {
+		// TODO log err
+		return errors.New("database was sad")
+	}
 
-	// TODO mark used
 	return nil
 }
 
diff --git a/towndb/towndb.go b/towndb/towndb.go
index 01e175d..9d03b04 100644
--- a/towndb/towndb.go
+++ b/towndb/towndb.go
@@ -221,4 +221,32 @@ func (c *AuthCode) Hydrate(db *sql.DB) error {
 	return stmt.QueryRow(c.Code).Scan(&c.ID, &c.Used, &c.Created)
 }
 
-// TODO other auth code as needed
+func (c *AuthCode) MarkUsed(db *sql.DB) error {
+	if c.ID == 0 {
+		return errors.New("not hydrated")
+	}
+
+	stmt, err := db.Prepare(`
+		UPDATE auth_codes SET used = 1 WHERE id = ?`)
+	if err != nil {
+		return err
+	}
+	defer stmt.Close()
+
+	result, err := stmt.Exec(c.ID)
+	if err != nil {
+		return err
+	}
+
+	var rowsAffected int64
+
+	if rowsAffected, err = result.RowsAffected(); err != nil {
+		return err
+	}
+
+	if rowsAffected == 0 {
+		return errors.New("no rows affected")
+	}
+
+	return nil
+}