Normally in a pipeline you can either use the[cf_export]({{site.baseurl}}/docs/codefresh-yaml/variables/#using-cf_export-command) command or write directly to the[/codefresh/volume/env_vars_to_export]({{site.baseurl}}/docs/codefresh-yaml/variables/#directly-writing-to-the-file) file.

Normally, in a pipeline you can either use the[cf_export]({{site.baseurl}}/docs/codefresh-yaml/variables/#using-cf_export-command) command or write directly to the[/codefresh/volume/env_vars_to_export]({{site.baseurl}}/docs/codefresh-yaml/variables/#directly-writing-to-the-file) file.

However inside a plugin you can also use the`/meta/env_vars_to_export` file that has the same semantics, but is used for exporting variables in the same scope as the plugin only.

However, inside a plugin you can also use the`/meta/env_vars_to_export` file that has the same semantics, but is used for exporting variables in the same scope as the plugin only.

The rules for using`/meta/env_vars_to_export` are:

- When the step-type (plugin) does not define the`return` schema, all the output variables from substeps will be projected and exported as the root step (they may override each other).

- When`return` schema is defined, only the variables that matched the definition will be exported as root step.

{% highlight yaml %}

{% raw %}

version: '1.0'

kind: step-type

metadata:

name: <account_name>/my-step

...

spec:

arguments: |-

{

...

}

returns: |-

{

"definitions": {},

"$schema": "http://json-schema.org/draft-07/schema#",

"type": "object",

"additionalProperties": true,

"patterns":[],

"required":[

"ROOT_VAR"

,

"properties": {

"ROOT_VAR": {

"type": "string",

"description": "an example variable"

}

}

}

steps:

export_my_variable:

title: "Exporting custom variable"

image: alpine

commands:

- echo MY_PLUGIN_VAR=SAMPLE_VALUE >> /meta/env_vars_to_export

- echo PLUGIN_VAR=Alice >> /meta/env_vars_to_export

- echo ROOT_VAR=Bob >> /meta/env_vars_to_export

read_my_variable:

title: "Reading custom variable"

image: alpine

commands:

- echo $MY_PLUGIN_VAR

- source /meta/env_vars_to_export

- echo $PLUGIN_VAR #Alice

- echo $ROOT_VAR #Bob

{% endraw %}

{% endhighlight %}

{% highlight yaml %}

{% raw %}

version: '1.0'

steps:

plugin:

type: <account_name>/my-step

echo:

image: alpine

commands:

- echo $PLUGIN_VAR #empty

- echo $ROOT_VAR #Bob

{% endraw %}

{% endhighlight %}