refactor: specific section for the gnu userland

.vscode/settings.json

@@ -121,6 +121,7 @@
         "turris",
         "twrp",
         "uncordon",
+        "userland",
         "usermod",
         "userspace",
         "winget",

knowledge base/gnu userland/README.md

@@ -0,0 +1,37 @@
+# GNU userland
+
+Most operating systems have two distinct parts: the **kernel** and the **userland**.
+
+Most Linux distributions use the [GNU userland][software].<br/>
+It contains system daemons, user applications, the GUI system (X11, KDE, etc.) and various libraries (such as SDL, Mesa, GNUstep, glibc, etc.).
+
+## Table of contents <!-- omit in toc -->
+
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## Further readings
+
+- [Software]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [GNU userland]
+
+<!--
+  References
+  -->
+
+<!-- Upstream -->
+[software]: https://www.gnu.org/software/
+
+<!-- In-article sections -->
+[further readings]: #further-readings
+
+<!-- Knowledge base -->
+[parallel]: parallel.md
+
+<!-- Others -->
+[gnu userland]: https://www.linux.org/threads/gnu-userland.11066/

knowledge base/gnu userland/parallel.md

@@ -50,8 +50,8 @@ parallel --tag "magick compare -metric NCC -quiet {} NULL: 2>&1; echo" \
 
 ## Further readings
 
-- GNU Parallel's [man page]
-- GNU Parallel's [tutorial]
+- [`man` page][man page]
+- [Tutorial]
 - [Obtaining exit status values from GNU parallel]
 
 <!--