Expand description
Fetches the environment variable key
from the current process, returning
None
if the variable isn’t set or there’s another error.
Note that the method will not check if the environment variable
is valid Unicode. If you want to have an error on invalid UTF-8,
use the var
function instead.
Errors
This function returns 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 may return an error if the environment variable’s value contains the NUL character.
Examples
use std::env;
let key = "HOME";
match env::var_os(key) {
Some(val) => println!("{key}: {val:?}"),
None => println!("{key} is not defined in the environment.")
}
Run