Fish history deleter

hdel.fish

#
# function hdel
#
# Interactively search and delete entries from fish shell history.
# Requires 'fzf' to be installed.
#
function hdel --description "Interactively delete items from Fish history"
    # 1. Dependency Check: Ensure fzf is installed.
    if not command -q fzf
        echo (set_color red)"Error: This function requires 'fzf' (fuzzy finder)."(set_color normal)
        echo "Please install it to continue. (e.g., 'sudo apt install fzf' or 'brew install fzf')"
        return 1
    end

    # 2. Get the history file path (backwards-compatible).
    set -l histfile
    if command -q fish_config && fish_config path history >/dev/null 2>&1
        set histfile (fish_config path history)
    else
        set histfile "$HOME/.local/share/fish/fish_history"
        if not test -f "$histfile"; set histfile "$HOME/.fish_history"; end
    end

    if not test -f "$histfile"
        echo (set_color red)"History file could not be found."(set_color normal)
        return 1
    end

    # 3. Present the history to the user via fzf for selection.
    #    - We extract only the command text for a clean list.
    #    - The user can select multiple lines with the Tab key.
    #    - A preview window shows the timestamp for context.
    set -l to_delete (
        grep '^- cmd: ' "$histfile" |
        sed 's/^- cmd: //' |
        fzf --multi --height=80% --reverse \
            --header="[ Fuzzy search history. Press TAB to mark for deletion, ENTER to confirm ]" \
            --preview='echo "Timestamp:"; grep -B 1 -F -- " {}" "$histfile" | head -n 1 | sed "s/  when: //"'
    )

    # 4. Check if the user cancelled (e.g., pressed Esc) or selected nothing.
    if test (count $to_delete) -eq 0
        echo "No commands selected. Aborting."
        return 0
    end

    # 5. Confirmation Step: Show what will be deleted and ask for confirmation.
    echo (set_color yellow)"The following (count(string trim $to_delete)) commands are marked for permanent deletion:"(set_color normal)
    for cmd in $to_delete
        echo "  - "(set_color red)$cmd(set_color normal)
    end
    echo

    read --prompt-str="Are you sure you want to proceed? (y/N) " confirm
    if test "$confirm" != "y" -a "$confirm" != "Y"
        echo "Aborted by user."
        return 0
    end

    # 6. Safety First: Create a backup before modifying anything.
    set -l backup_file "$histfile.bak."(date +%F-%T)
    cp -p "$histfile" "$backup_file"
    echo "↪ Safety backup created at:" (set_color blue)$backup_file(set_color normal)

    # 7. Core Deletion Logic using AWK.
    #    This is robust and correctly handles the 2-line structure of fish history.
    set -l temp_file (mktemp)

    # Build an awk script that knows which commands to delete.
    # We pass the commands from our fish list into an awk associative array.
    set -l awk_script 'BEGIN {'
    for cmd in $to_delete
        # Escape backslashes and double-quotes for the awk string literal
        set -l escaped_cmd (string escape --style=c $cmd)
        set awk_script "$awk_script to_delete[\"$escaped_cmd\"] = 1;"
    end
    # The main awk logic that filters the file.
    set awk_script "$awk_script" '
        }
        # For every line in the history file...
        {
            # Is it a command line?
            if (match($0, /^- cmd: (.*)/, m)) {
                # Is the extracted command text (m[1]) in our to_delete list?
                if (m[1] in to_delete) {
                    # Yes. So we do nothing. This effectively deletes both
                    # this line and the "when:" line we saved just before it.
                } else {
                    # No. This is a command to keep. Print its saved "when:"
                    # line, and then print the command line itself.
                    print saved_line
                    print $0
                }
            } else {
                # It must be a "when:" line. Save it for the next iteration.
                saved_line = $0
            }
        }
    '

    # Execute the awk script.
    awk "$awk_script" "$histfile" > "$temp_file"

    # 8. Replace the original history file and reload the session.
    mv "$temp_file" "$histfile"
    history clear-session
    history merge

    echo (set_color green)"✅ Successfully deleted (count $to_delete) history entries."(set_color normal)
end