https://github.com/mermaid-js/mermaid-cli
Command line tool for the Mermaid library
https://github.com/mermaid-js/mermaid-cli
cli diagrams mermaid
Last synced: 8 days ago
JSON representation
Command line tool for the Mermaid library
- Host: GitHub
- URL: https://github.com/mermaid-js/mermaid-cli
- Owner: mermaid-js
- License: mit
- Created: 2020-05-18T07:26:06.000Z (almost 5 years ago)
- Default Branch: master
- Last Pushed: 2025-04-14T08:00:41.000Z (about 1 month ago)
- Last Synced: 2025-04-18T06:23:04.340Z (28 days ago)
- Topics: cli, diagrams, mermaid
- Language: JavaScript
- Homepage:
- Size: 2.96 MB
- Stars: 2,923
- Watchers: 36
- Forks: 281
- Open Issues: 77
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
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README
# mermaid-cli
[](https://www.npmjs.com/package/@mermaid-js/mermaid-cli)
[](https://www.npmjs.com/package/@mermaid-js/mermaid-cli)
[](https://hub.docker.com/r/minlag/mermaid-cli)
[](https://github.com/mermaid-js/mermaid-cli/actions/workflows/compile-mermaid.yml)
[](https://percy.io/Mermaid/mermaid-cli)
[](https://join.slack.com/t/mermaid-talk/shared_invite/enQtNzc4NDIyNzk4OTAyLWVhYjQxOTI2OTg4YmE1ZmJkY2Y4MTU3ODliYmIwOTY3NDJlYjA0YjIyZTdkMDMyZTUwOGI0NjEzYmEwODcwOTE)
This is a command-line interface (CLI) for [mermaid](https://mermaid.js.org/). It takes a mermaid definition file as input and generates an svg/png/pdf file as output.
## Installation
```sh
npm install -g @mermaid-js/mermaid-cli
```
## Usage
Convert Mermaid mmd Diagram File To SVG
```sh
mmdc -i input.mmd -o output.svg
```
> **Note**
>
> See [Alternative installations](#alternative-installations) if you don't want to install the package globally.
>
> Locate how to call the mmdc executable for your preferred method
> i.e. Docker, Yarn, NPM, local install, etc.
## Examples
### Create A PNG With A Dark Theme And Transparent Background
```sh
mmdc -i input.mmd -o output.png -t dark -b transparent
```
### Animating an SVG file with custom CSS
The `--cssFile` option can be used to inline some custom CSS.
Please see [./test-positive/flowchart1.css](test-positive/flowchart1.css) for an example of a CSS file that has animations.
**Warning**: If you want to override `mermaid`'s [`themeCSS`](https://mermaid.js.org/config/schema-docs/config.html#themecss), we recommend instead adding `{"themeCSS": "..."})` to your mermaid `--configFile`. You may also need to use [`!important`](https://developer.mozilla.org/en-US/docs/Web/CSS/important) to override mermiad's `themeCSS`.
**Warning**: Inline CSS files may be blocked by your browser, depending on the [HTTP Content-Security-Policy header](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy) of the website that hosts your SVG.
```sh
mmdc --input test-positive/flowchart1.mmd --cssFile test-positive/flowchart1.css -o docs/animated-flowchart.svg
```
Example output: docs/animated-flowchart.svg
### Transform a markdown file with mermaid diagrams
```sh
mmdc -i readme.template.md -o readme.md
```
This command transforms a markdown file itself. The mermaid-cli will find the mermaid diagrams, create SVG files from them and refer to those in the markdown output.
This:
~~~md
### Some markdown
```mermaid
graph
[....]
```
### Some more markdown
```mermaid
sequenceDiagram
[....]
```
### Mermaid with custom title/desc
```mermaid
graph
accTitle: My title here
accDescr: My description here
A-->B
```
~~~
Becomes:
```md
### Some markdown
### Some more markdown
### Mermaid with custom title/desc
```
### Piping from stdin
You can easily pipe input from stdin. This example shows how to use a heredoc to
send a diagram as stdin to mermaid-cli (mmdc).
```sh
cat << EOF | mmdc --input -
graph TD
A[Client] --> B[Load Balancer]
EOF
```
### See All Available Options
```sh
mmdc -h
```
# Alternative installations
## Use Docker/Podman:
```sh
docker pull minlag/mermaid-cli
```
or pull from Github Container Registry
```sh
docker pull ghcr.io/mermaid-js/mermaid-cli/mermaid-cli
```
or e.g. version 8.8.0
```sh
docker pull minlag/mermaid-cli:8.8.0
```
The container looks for input files in `/data`. So for example, if you have a
diagram defined on your system in `/path/to/diagrams/diagram.mmd`, you can use
the container to generate an SVG file as follows:
```sh
docker run --rm -u `id -u`:`id -g` -v /path/to/diagrams:/data minlag/mermaid-cli -i diagram.mmd
```
Or, if using [Podman](https://podman.io/), instead do:
```sh
podman run --userns keep-id --user ${UID} --rm -v /path/to/diagrams:/data:z ghcr.io/mermaid-js/mermaid-cli/mermaid-cli -i diagram.mmd
```
The key differences in the podman command versus the docker command are:
- The addition of the `--userns keep-id` argument. This allows the container to keep the same UID as the current user's UID in the container namespace instead of mapping to a subuid. Docs can be found [here](https://docs.podman.io/en/latest/markdown/options/userns.container.html)
- The addition of `:z` to the end of the volume mapping. This instructs podman to relabel the files in the volume with the SELinux label `container_file_t`, which allows processes in the container to access the files. See the "Labeling Volume Mounts" section [here](https://docs.podman.io/en/latest/markdown/podman-run.1.html#volume-v-source-volume-host-dir-container-dir-options) for more info.
In previous version, the input files were mounted in `/home/mermaidcli`. You can
restore this behaviour with the `--workdir` option:
```sh
docker run [...] --workdir=/home/mermaidcli minlag/mermaid-cli [...]
```
## Use Node.JS API
It's possible to call `mermaid-cli` via a Node.JS API.
Please be aware that **the NodeJS API is not covered by semver**, as `mermaid-cli` follows
`mermaid`'s versioning.
```js
import { run } from "@mermaid-js/mermaid-cli"
await run(
"input.mmd", "output.svg", // {optional options},
)
```
## Install locally
Some people are [having issues](https://github.com/mermaidjs/mermaid.cli/issues/15)
installing this tool globally. Installing it locally is an alternative solution:
```
npm install @mermaid-js/mermaid-cli
./node_modules/.bin/mmdc -h
```
### Run with npx
[`npx`](https://www.npmjs.com/package/npx) is installed by default with NPM. It
downloads and runs commands at the same time. To use Mermaid CLI with npx, you
need to use the `-p` flag because the package name is different than the command
it installs (`mmdc`). `npx -p @mermaid-js/mermaid-cli mmdc -h`
## Install with [brew](https://brew.sh)
> **Warning**
>
> This method of installation is no longer supported.
> For more details, see the [discussion](https://github.com/mermaid-js/mermaid-cli/issues/288).
> An old version of mermaid-cli can be installed with brew.
> ```sh
> brew install mermaid-cli
> ```
## Known issues
1. [Linux sandbox issue](docs/linux-sandbox-issue.md)
2. [Docker permission denied issue](docs/docker-permission-denied.md)
3. [How to setup up mermaid to use already installed chromium?](docs/already-installed-chromium.md)
## For contributors
Contributions are welcome. See the [contribution guide](CONTRIBUTING.md).