Function pathsearch::find_executable_in_path

pub fn find_executable_in_path<O: AsRef<OsStr> + ?Sized>(
    command: &O
) -> Option<PathBuf>

Resolves the first matching candidate command from the current process environment using the platform appropriate rules. On Unix systems this will search the PATH environment variable for an executable file. On Windows systems this will search each entry in PATH and return the first file that has an extension listed in the PATHEXT environment variable.