# Function std::env::var

1.0.0 · source ·

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

Expand description

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}"),
    }

Run