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

tldr/linux/unshare

@@ -0,0 +1,17 @@
+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# unshare
+
+> Execute a command in new user-defined namespaces.
+> More information: <https://www.kernel.org/doc/html/latest/userspace-api/unshare.html>.
+
+- Execute a command without sharing access to connected networks:
+
+`unshare --net {{command}} {{command_arguments}}`
+
+- Execute a command as a child process without sharing mounts, processes, or networks:
+
+`unshare --mount --pid --net --fork {{command}} {{command_arguments}}`