Docker Run Command Builder

The -d (detached) flag runs the container in the background and prints the container ID. Without it, the container runs in the foreground and attaches your terminal to its output. Use -d for long-running services like web servers or databases.

The --rm flag automatically deletes the container's filesystem once it exits. Without --rm, stopped containers remain on disk and can be restarted or inspected later. Use --rm for one-off tasks and short-lived containers to avoid accumulating stopped containers.

The -p flag maps a host port to a container port using the format host:container (e.g., -p 8080:80). Traffic arriving on port 8080 of your host machine is forwarded to port 80 inside the container. You can publish multiple ports by repeating the -p flag.

Bind mounts (e.g., -v ./data:/data) map a specific path on your host into the container, making them ideal for development where you want live code changes. Named volumes (e.g., -v mydata:/data) are managed by Docker and are better for production data persistence because they are independent of the host directory structure.

Docker offers four restart policies: 'no' (never restart, the default), 'always' (restart regardless of exit code, including on daemon start), 'unless-stopped' (like always but respects manual stops), and 'on-failure' (only restart on non-zero exit codes). Use 'unless-stopped' for services you always want running, and 'on-failure' for tasks that should retry on errors but not run indefinitely.