Subject: Document sleep infinity

From: 積丹尼 Dan Jacobson <[email-masked]>
Date: Tue, 26 Feb 2019 23:37:33 +0800

$ man sleep | grep -ic infinity
0
$ sleep --help | grep -ic infinity
0
$ info sleep | grep -ic infinity
0
$ /bin/sleep infinity #But it still works, so please document it.