verifyonly

Verifyonly is a term used to describe a mode of operation in software tools where the primary goal is to validate or verify aspects of a system, input, or configuration without performing any actions that would modify state or produce side effects. In this mode, the process runs checks, but stops short of applying changes, installing components, or mutating data.

This mode is commonly employed in deployment, configuration management, packaging, and data processing workflows. In deployment and configuration contexts, verify-only acts as a preflight or validation step that ensures compatibility, correctness, or compliance before a real change is attempted. In software packaging and installation, a verify-only pass may check package integrity, dependencies, and platform requirements to catch issues prior to installation. In data processing or migration scenarios, a verify-only run can compare current states to expected schemas or quality criteria without performing the transformation or write operations.

Operational characteristics typically include performing a full set of validations, producing a summary report, and exiting with a success or failure status based on the results. Outputs often include detailed logs or a report identifying any problems found. A verify-only mode is usually invoked via a dedicated flag or option, such as a boolean switch or a specific command name, for example --verify-only or verifyOnly in some tooling ecosystems. It is distinct from a dry-run or check mode in that it emphasizes validation rather than simulation, though the terms can overlap in practice.

Limitations of verify-only include the possibility that validations do not perfectly predict issues that will appear during actual execution, and some problems may only become apparent when changes are applied. See also dry-run, check mode, and preflight validation.