Put a command in history without executing it

Option four (as an answer to the title of the question, not its explanation ;-):

• print -S "this line goes to the history"

Excerpt from zshbuiltins(1): "print -S Place the results in the history list instead of on the standard output. In this case only a single argument is allowed; it will be split into words as if it were a full shell command line. The effect is similar to reading the line from a history file with the HIST_LEX_WORDS option active."

Three options:

• zsh has the keyboard shortcut Alt + Q by default that pushes the current line.

  Use it like this:

  1. Type command.

  2. Press Alt + Q.

  3. Execute othercommand.

  4. command will reappear.

  Technically, this doesn't put it in the history. Also, if you need to execute another command before command, you have to press Alt + Q again.

• Also by default, the keyboard shortcuts Ctrl + U and Ctrl + Y cut and yank (paste) the current line.

  Use them like this:

  1. Type command.

  2. Press Ctrl + U.

  3. Execute othercommand.

  4. Press Ctrl + Y.

  5. command will reappear.

  This would work in bash as well and it uses its own clipboard, i.e., they contents of the clipboard managed by Ctrl + (Shift +) C / V and select / middle-click will remain unaltered.

• Last but not least, you can permanently enable comments on the command-line by executing

  echo setopt interactivecomments >> ~/.zshrc
  

  Alt + # doesn't work here, but Ctrl + A / Home, #, Enter achieves the same result.

To see all available keyboard shortcuts, execute

bindkey

A widgetification of @mpy's answer, add this to your .zshrc

to-history() { print -S $BUFFER ; BUFFER= }
zle -N to-history
bindkey 'œ' to-history

Note: œ is what I get on a Mac for alt/option-q, adjust for your terminal

If you're using vi mode, then press ESC to enter normal mode, and then Shift+3 (#). This will put the commented out command in history.