Copy contents to clipboard form command line (Ubuntu, macOS)

macOS

macOS comes with pbcopy

1pbcopy < ~/.ssh/id_rsa.pub
2
3# or 
4
5cat ~/.ssh/id_rsa.pub | pbcopy

Ubuntu

On Ubuntu you can use xclip

1sudo apt install xclip
2xclip -selection clipboard -i < inputFile
3
4# xclip -sel c < inputFile

• clipboard is a parameter for -selection
• -i means inoput (standard input or file). Since file is default, you can omit the -i in most cases

-i, -in
      read text into X selection from standard input or files (default)

-o, -out
      print the selection to standard out (generally for piping to a file or program)

-selection
      specify which X selection to use, options are "primary" to use XA_PRIMARY (default), "secondary" for XA_SECONDARY or "clipboard" for XA_CLIPBOARD

NOTE: xclip and xsel are X11 utilities, they manipulate the X11 selections, so can only be used in a X11 environment where $DISPLAY is set. Running in a terminal only context (e.g. WSL or headless) will give you this error:

1Error: Can't open display: (null)