ang/janet/blob/4e5889e/src/core/os.c#L2238">source</a></span> <pre class="binding-text">(os/umask mask)

Set a new umask, returns the old umask.</pre><a href="https://janetdocs.org/os/umask">Community Examples</a></div><hr><div class="binding"><span id="os/which" class="binding-sym">os/which</span> <span class="binding-type">cfunction</span> <span class="binding-type"><a href="https://github.com/janet-lang/janet/blob/4e5889e/src/core/os.c#L132">source</a></span> <pre class="binding-text">(os/which)

Check t