chore(kb): review and add articles for commands i stored somewhere else

knowledge base/pkill.md

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+# pkill
+
+> TODO
+
+Command-line tools that sends signals to the processes of a running program based on given criteria.
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+   1. [Sources](#sources)
+
+## TL;DR
+
+Basically a wrapper around `pgrep` and `kill`.
+
+Part of the `procps` (or `procps-ng`) package, which is pre-installed on nearly all Linux distributions.
+
+The processes can be specified by:
+
+- Their **full** or **partial** name.
+- A user running the process.
+- Other attributes.
+
+Returns 0 when at least one running process matched the requested pattern. Otherwise, its exit code is `1`.
+
+<details>
+  <summary>Setup</summary>
+
+```sh
+apt install 'procps'
+brew install 'proctools'  # or brew install 'pkill'
+dnf install 'procps-ng'
+yum install 'procps-ng'
+```
+
+</details>
+
+<details>
+  <summary>Usage</summary>
+
+```sh
+# Gracefully stop all processes of programs matching the given pattern
+pkill 'pattern'
+pkill -15 'pattern'
+pkill -TERM 'pattern'
+pkill -SIGTERM 'pattern'
+pkill --signal 'TERM' 'pattern'
+
+# Display what processes are sent signals
+pkill -e …
+pkill --echo …
+
+# Only kill processes of specific users' *real* id
+pkill -u 'mark' …
+pkill --uid 'mark,john' …
+```
+
+</details>
+
+<details>
+  <summary>Real world use cases</summary>
+
+```sh
+pkill -HUP 'nginx'
+pkill --signal 'TERM' --exact 'yes'
+pkill '^ssh$'
+pkill -9 -f "ping 8.8.8.8"
+pkill -KILL -u 'mike' 'gdm'
+```
+
+</details>
+
+## Further readings
+
+- [Website]
+- [Codebase]
+
+### Sources
+
+- [Documentation]
+- [Pkill Command in Linux]
+
+<!--
+  Reference
+  ═╬═Time══
+  -->
+
+<!-- In-article sections -->
+<!-- Knowledge base -->
+<!-- Files -->
+<!-- Upstream -->
+[Codebase]: https://github.com/project/
+[Documentation]: https://website/docs/
+[Website]: https://website/
+
+<!-- Others -->
+[Pkill Command in Linux]: https://linuxize.com/post/pkill-command-in-linux/