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website/versioned_docs/version-latest/experiments/env_precedence.mdx

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+---
+slug: '/experiments/env-precedence'
+---
+
+# Env Precedence (#1038)
+
+:::caution
+
+All experimental features are subject to breaking changes and/or removal _at any
+time_. We strongly recommend that you do not use these features in a production
+environment. They are intended for testing and feedback only.
+
+:::
+
+:::warning
+
+This experiment breaks the following functionality:
+
+- environment variable will take precedence over OS environment variables
+
+:::
+
+:::info
+
+To enable this experiment, set the environment variable:
+`TASK_X_ENV_PRECEDENCE=1`. Check out [our guide to enabling
+experiments][enabling-experiments] for more information.
+
+:::
+
+Before this experiment, the OS variable took precedence over the task
+environment variable. This experiment changes the precedence to make the task
+environment variable take precedence over the OS variable.
+
+Consider the following example:
+
+```yml
+version: '3'
+
+tasks:
+  default:
+    env:
+      KEY: 'other'
+    cmds:
+      - echo "$KEY"
+```
+Running `KEY=some task` before this experiment, the output would be `some`, but
+after this experiment, the output would be `other`.
+
+If you still want to get the OS variable, you can use the template function env
+like follow : `{{env "OS_VAR"}}`.
+
+```yml
+version: '3'
+
+tasks:
+  default:
+    env:
+      KEY: 'other'
+    cmds:
+      - echo "$KEY"
+      - echo {{env "KEY"}}
+```
+Running `KEY=some task`, the output would be `other` and `some`.
+
+Like other variables/envs, you can also fall back to a given value using the
+default template function:
+```yml
+MY_ENV: '{{.MY_ENV | default "fallback"}}'
+```
+
+{/* prettier-ignore-start */}
+[enabling-experiments]: ./experiments.mdx#enabling-experiments
+{/* prettier-ignore-end */}