alues varied with
the underlying operating system. There are new portable functions like
<a href="/pkg/os/#IsPermission"><code>IsPermission</code></a>
to test common error properties, plus a few new error values
with more Go-like names, such as
<a href="/pkg/os/#ErrPermission"><code>ErrPermission</code></a>
and
<a href="/pkg/os/#ErrNoEnv"><code>ErrNoEnv</code></a>.
</p>

<p>
The <code>Getenverror</code> function has been removed. To distinguish
between a non-existent environment variable and an empty string