xsel

X11 selection and clipboard manipulation tool. More information: https://manned.org/xsel.

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

echo 123 | xsel -ib

• Use the contents of a file as input of the clipboard:

cat {{path/to/file}} | xsel -ib

• Output the clipboard's contents into the terminal (equivalent to Ctrl + V):

xsel -ob

• Output the clipboard's contents into a file:

xsel -ob > {{path/to/file}}

• Clear the clipboard:

xsel -cb

• Output the X11 primary selection's contents into the terminal (equivalent to a mouse middle-click):

xsel -op