Which command is used to edit the sudoers file safely?

The command used to edit the sudoers file safely is visudo. This tool is specifically designed for editing the sudoers file because it provides a number of safety features that help prevent syntax errors, which can lock users out of sudo access if not handled carefully.

When using visudo, it locks the sudoers file, ensuring that no other instances can modify it simultaneously, which prevents conflicts and data corruption. Additionally, visudo performs a syntax check before saving the file, alerting the user to any errors in the configuration. This is critical since a misconfigured sudoers file can lead to security vulnerabilities or operational issues within a system.

The other provided commands, while they may seem plausible at first glance, do not offer the same level of safety and error-checking features that visudo does. Therefore, using visudo is the recommended practice for editing the sudoers file.