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

tldr/linux/xdg-open

@@ -0,0 +1,29 @@
+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# xdg-open
+
+> Opens a file or URL in the user's preferred application.
+> More information: <https://portland.freedesktop.org/doc/xdg-open.html>.
+
+- Open the current directory in the default file explorer:
+
+`xdg-open .`
+
+- Open a URL in the default browser:
+
+`xdg-open {{https://example.com}}`
+
+- Open an image in the default image viewer:
+
+`xdg-open {{path/to/image}}`
+
+- Open a PDF in the default PDF viewer:
+
+`xdg-open {{path/to/pdf}}`
+
+- Display help:
+
+`xdg-open --help`