1 files changed, 26 insertions, 0 deletions
diff --git a/structopt/examples/env.rs b/structopt/examples/env.rs
new file mode 100644
index 0000000..0477089
--- /dev/null
+++ b/structopt/examples/env.rs
@@ -0,0 +1,26 @@
+//! How to use environment variable fallback an how it
+//! interacts with `default_value`.
+
+use structopt::StructOpt;
+
+/// Example for allowing to specify options via environment variables.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "env")]
+struct Opt {
+    // Use `env` to enable specifying the option with an environment
+    // variable. Command line arguments take precedence over env.
+    /// URL for the API server
+    #[structopt(long, env = "API_URL")]
+    api_url: String,
+
+    // The default value is used if neither argument nor environment
+    // variable is specified.
+    /// Number of retries
+    #[structopt(long, env = "RETRIES", default_value = "5")]
+    retries: u32,
+}
+
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:#?}", opt);
+}