feat: added article about coreutils' timeout

knowledge base/timeout.md

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+# `timeout`
+
+Start a command and kill it if still running after a given duration.<br/>
+The command must not be a special built-in utility.
+
+Part of GNU coreutils.
+
+## Table of contents <!-- omit in toc -->
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## TL;DR
+
+```sh
+# Send the default TERM signal after 20s to a short-living command.
+# It terminates before the given duration limit, so 'timeout' returns with the
+# same exit status as the command.
+timeout 20 sleep 1
+
+# Send the INT signal after 5s to the 'sleep' command.
+# Returns after 5 seconds with exit status 124 to indicate the sending of the
+# interruption signal.
+timeout -s INT 5 sleep 20
+
+# Likewise, but the command will ignore the INT signal due to it being started
+# via 'env --ignore-signal'.
+# 'sleep' will terminate regularly after the full 20 seconds.
+# 'timeout' will still return with exit status 124 to indicate the sending of
+# the interruption signal.
+timeout -s INT 5s env --ignore-signal=INT sleep 20
+
+# Likewise, but will also send the KILL signal 3 seconds after the initial INT
+# signal.
+# 'sleep' is forcefully terminated after about 303 seconds (5m + 3s), and
+# 'timeout' returns with an exit status of 137 to indicate the sending of the
+# termination signal.
+timeout -s INT -k 3s 5m env --ignore-signal=INT sleep 600
+```
+
+## Further readings
+
+- [Website]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [cheat.sh]
+
+<!--
+  references
+  -->
+
+<!-- project -->
+[website]: https://www.gnu.org/software/coreutils/timeout
+
+<!-- article sections -->
+[further readings]: #further-readings
+
+<!-- knowledge base -->
+<!-- others -->
+[cheat.sh]: https://cheat.sh/timeout