Function tracing_core::stdlib::env::var

pub fn var<K>(key: K) -> Result<String, VarError>
where
    K: AsRef<OsStr>,

Fetches the environment variable key from the current process.

Errors

This function will return an error if the environment variable isn’t set.

This function may return an error if the environment variable’s name contains the equal sign character (=) or the NUL character.

This function will return an error if the environment variable’s value is not valid Unicode. If this is not desired, consider using var_os.

Examples

use std::env;

let key = "HOME";
match env::var(key) {
    Ok(val) => println!("{key}: {val:?}"),
    Err(e) => println!("couldn't interpret {key}: {e}"),
}