Use a command's output as input of the clip[b]oard (equivalent to Ctrl + C)

X11 selection and clipboard manipulation tool.
More information: <https://manned.org/xsel>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

echo 123 | xsel -ib

click the source code to copy install xsel on any operating system with command-not-found.com