Copying previous commands with fzf and zsh

Jul 14, 2022

Sometimes I want to copy a command I previously typed in my shell to the clipboard. It may be for documentation, note-taking, writing a script, setting up an Ansible playbook, sending to someone… You name it.

While I could always search the terminal window for it and select it, I have set up an alias that makes things much easier and less error-prone:

alias hy="
  fc -ln 0 |
  awk '!a[\$0]++' |
  fzf --tac --multi --header 'Copy history' |
  xsel --clipboard
"

This will perform the task silently. If you prefer a confirmation message after each copy, a clean approach is to convert the alias into a function like this:

hy() {
  local -r entry="$(fc -ln 0 | awk '!a[$0]++' | fzf --tac --multi --header 'Copy history')"
  [[ -n "$entry" ]] && xsel --clipboard <<< "$entry" >/dev/null && echo "Copied to clipboard." >&2
}

Until now, we assumed the system was running on X11. Now, let’s make it work on Wayland too:

hy() {
  local copy_cmd
  case "$XDG_SESSION_TYPE" in
    x11)     copy_cmd="xsel --clipboard" ;;
    wayland) copy_cmd="wl-copy" ;;
    *) echo "Session type not detected."; return ;;
  esac

  local -r entry="$(fc -ln 0 | awk '!a[$0]++' | fzf --tac --multi --header 'Copy history')"
  [[ -n "$entry" ]] && eval $copy_cmd <<< "$entry" >/dev/null && echo "Copied to clipboard." >&2
}

In action

Typing hy (short for “history yank”) brings fzf with a list of your most recent commands. You can browse them using the keyboard or perform a fuzzy search. Pressing Enter copies the selected command to the clipboard.

Even better, if you enable multi-selection on fzf, you can select multiple commands using Tab. They will be copied to the clipboard one per line.

The how

Explaining each part:

• fc -ln 0: On zsh, this returns the entire shell history, one command per line. If you use Bash or another shell, just replace it with the equivalent command.
• awk '!a[\$0]++': The history is piped to awk, which removes duplicate entries. Without this cleaning, fzf may display multiple repeated lines, which can be annoying.
• fzf --tac --header 'Copy history': The result is piped to fzf. The --tac argument reverses the order (as we want the last commands to be at the top), while --multi allows multiple selection. We also add a prompt message using --header.
• wl-copy (on Wayland) or xsel --clipboard (on X11): Finally, the commands selected are copied to the clipboard.

Needless to say, be sure to have the mentioned tools installed on your system for this to work.

Have comments? Email me.

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