feat: tagging in linux

knowledge base/linux/setfattr.md

@@ -0,0 +1,42 @@
+# `setfattr`
+
+## Table of contents <!-- omit in toc -->
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## TL;DR
+
+```sh
+# Add extended attributes.
+setfattr -n 'name' -v 'value' 'path/to/file.1' … 'path/to/file.N'
+
+# Remove extended attributes.
+setfattr -x 'name' 'path/to/file.1' … 'path/to/file.N'
+```
+
+## Further readings
+
+- [`getfattr`][getfattr]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [`man` page][man page]
+- [Tag files in GNU/Linux]
+
+<!--
+  References
+  -->
+
+<!-- In-article sections -->
+[further readings]: #further-readings
+
+<!-- Knowledge base -->
+[getfattr]: getfattr.md
+[tag files in gnu/linux]: tag%20files.md
+
+<!-- Others -->
+[man page]: https://linux.die.net/man/1/setfattr