Which command is used to verify configuration syntax without actually applying the changes?

The command that is used to verify configuration syntax without applying any changes is "commit check." When you use this command in Junos, it checks the pending configuration changes for syntax errors or issues that would prevent the configuration from being successfully committed. This allows network engineers to ensure that any changes they intend to make are valid and will not disrupt network operations when they are eventually applied.

This command is particularly useful in complex configurations where a misconfiguration could lead to network downtime or degraded performance. By verifying the configuration beforehand, engineers can catch and address potential problems before they affect the live network.

The other commands do not serve the same purpose. For example, "commit apply" actually applies the configuration changes, while "verify config" is not a recognized command in Junos. "Show configuration" simply displays the current configuration but does not provide feedback on the validity of any pending changes.