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

tldr/nix3-flake

@@ -0,0 +1,29 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# nix flake
+
+> Manage Nix flakes.
+> More information: <https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-flake.html>.
+
+- Create a new flake (just the `flake.nix` file) from the default template, in the current directory:
+
+`nix flake init`
+
+- Update all inputs (dependencies) of the flake in the current directory:
+
+`nix flake update`
+
+- Update a specific input (dependency) of the flake in the current directory:
+
+`nix flake lock --update-input {{input}}`
+
+- Show all the outputs of a flake on github:
+
+`nix flake show {{github:owner/repo}}`
+
+- Display help:
+
+`nix flake --help`