A command-line argument is a value supplied to a program when it starts, such as an option, filename, or credential. Programs and automation tools use arguments to control what they do. Depending on the operating system and configuration, arguments may be visible to other processes or recorded in diagnostic output, monitoring systems, or logs.
This matters in cybersecurity because secrets placed in arguments can be exposed beyond the process that needs them. For example, an agent or script might pass an API token directly in a command; that token could then persist in logs or be visible to users with sufficient system access. Prefer safer mechanisms, such as restricted secret stores or protected input channels, and avoid logging sensitive values. Limit who can inspect process details and use short-lived credentials where practical.