Docker & Containers
Set an image, add only the mappings you need, then review the generated POSIX command.
docker run \ --detach \ 'nginx:alpine'
POSIX sh output for macOS, Linux or WSL. Paths are literal; variables and ~ are not expanded.
Configuration stays in this browser. No Docker connection, registry request or command execution.
Up to 20 rows per group. CPU: 0.001–1024. Memory: integer b/k/m/g, at least 6 MiB; blank leaves it unset.
Command preview is current.
A container launch often starts with an image name and a handful of settings copied from different notes. The Docker Run builder brings those choices into one form so you can check which side of a port mapping belongs to the host and which path belongs inside the container.
Build a command for a new container without guessing the order of flags. Your image keeps its default entrypoint and command; an empty option is omitted, not replaced with an invented value. The initial nginx:alpine example runs detached and publishes no ports until you add them.
The Docker Run builder turns individual host ports, container ports, mount sources and ENV values into distinct arguments. You can review the generated mapping without manually balancing quotes around a path such as /opt/site files. Changing a setting immediately disables export of the old command.
An all-interface port, a privileged container or a sensitive bind source earns a visible warning. ENV values start masked in both the fields and the command preview. Showing them is an explicit choice before a complete command can be copied; masking is a display feature, not encryption.
A new port row starts with 127.0.0.1 and TCP. That limits the requested binding to loopback. Clearing the address requests all interfaces; it does not mean that Docker chooses a private address. The container port must still match the service inside the image.
Choose bind for an existing absolute path on the Docker host, or volume for storage managed by Docker. New rows are read-only. A writable database volume needs that switch changed deliberately; the tool does not infer application requirements.
Automatic building waits 350 ms. Turn it off to edit several rows, then use Build command or Ctrl/Cmd+Enter. Check any warning and reveal ENV values only when you are ready to export. Example, clear and row removal show a preview and support one undo.
Each row emits one --publish argument with its IPv4 binding, host port, container port and TCP or UDP protocol. Overlapping bindings for the same host port and protocol are rejected, while TCP and UDP can share a number. This checks the form, not whether another process already owns the port.
Bind mounts point to host files or directories; named volumes let Docker manage storage. The output uses --mount with an explicit type and optional readonly flag. Duplicate normalized container targets are rejected so one row cannot silently hide another mapping.
The Docker command generator keeps spaces, equals signs, apostrophes and dollar signs within one argument. An empty value generates KEY= explicitly. Duplicate keys are errors, and no value is read from the browser computer's environment. Shell substitution is never used to fill a value.
Combine detached mode, interactive TTY, a container name, restart policy, CPU and memory limits. Remove-on-exit conflicts with every non-no restart policy and blocks generation. Blank resource fields add no limit; choosing a limit is not a reservation of hardware capacity.
Add one row for each mapping, up to 20 per group. Port rows keep the host and container numbers separate. Mount rows use a distinct source, target and type; there is no comma-separated list pasted into a single mapping. Repeated targets or overlapping host bindings are rejected.
Enter the value without adding shell quotes yourself. Spaces and punctuation are preserved, and the output quotes the entire KEY=value argument. For example, the literal text $HOME stays that text rather than becoming a directory. Newlines and control characters are rejected.
These are runtime flags for docker run, not Dockerfile instructions. In this form, remove-on-exit can be used only with restart set to no. For a persistent service choose a restart policy and leave automatic removal off; for a temporary container use --rm without that policy.
A named volume is managed by Docker and selected by its name. A bind mount points to a particular host path and can expose or change host data. Choose the type explicitly. With --mount, a missing bind source is normally an error; the page cannot check whether it exists.
No. This page creates one docker run command and keeps the image’s own startup command. A Compose file can describe several services, networks and dependencies, which need a separate model. The generated text should not be pasted into a YAML service definition as though it were Compose.
Does the preview differ from the Docker documentation?
Use the Docker Run builder to check the exact flags you intend to run. Resolve errors, inspect exposure warnings and confirm the Docker host before exporting.