How do I send a visual selection to an external command as input without replacing the selected text?

Explanation

The :'<,'>w !{cmd} command writes the visually selected lines to the stdin of an external shell command — without modifying the buffer. This is distinct from :'<,'>!{cmd}, which pipes the selection through the command and replaces it with the output.

This is useful when you want to pass selected text to a tool for side-effects only: copying to the clipboard, counting words, linting, running tests, or sending code to a REPL.

How it works

• '<,'> is the range of the last visual selection (automatically inserted when you press : in visual mode)
• w is the write command, which writes the range to a destination
• !{cmd} specifies an external shell command as the destination — the lines are piped to its stdin
• The buffer is not modified

Example

Visually select a block of Python code with V then j a few times, then:

:'<,'>w !python3

This executes the selected lines as Python code and shows the output — the buffer is unchanged.

Other practical uses:

:'<,'>w !wc -w          " count words in selection
:'<,'>w !pbcopy         " copy selection to macOS clipboard
:'<,'>w !xclip -sel clip " copy selection to Linux clipboard
:'<,'>w !xargs open     " open URLs in selection in browser

Tips

• Compare with :'<,'>!{cmd} which replaces the selected text with the command output
• Use :w !{cmd} (without a range) to send the entire buffer to a command
• The command's output appears in the Vim message area; use :redir to capture it