Move pages under tldr, lint run.sh, update docs

tldr/osx/date

@@ -0,0 +1,25 @@
+---
+syntax: markdown
+tags: [tldr, osx]
+source: https://github.com/tldr-pages/tldr.git
+---
+# date
+
+> Set or display the system date.
+> More information: <https://keith.github.io/xcode-man-pages/date.1.html>.
+
+- Display the current date using the default locale's format:
+
+`date +%c`
+
+- Display the current date in UTC and ISO 8601 format:
+
+`date -u +%Y-%m-%dT%H:%M:%SZ`
+
+- Display the current date as a Unix timestamp (seconds since the Unix epoch):
+
+`date +%s`
+
+- Display a specific date (represented as a Unix timestamp) using the default format:
+
+`date -r 1473305798`