Tinkering with zsh and bash based on a cli proxy and formatter idea derived from Simon's post on mastodon: https://mastodon.social/@simonbs/116142608738376660

cli_formatter.sh

#!/usr/bin/env bash
# =============================================================================
# An original idea: https://mastodon.social/@simonbs/116142608738376660
# and a highly experimental terminal command formatter; kind of ... proxy'n
# formatter for long terminal commands
# =============================================================================
# Installation:
#   source ~/.bashrc  or  source ~/.zshrc
#   add to ~/.bashrc or ~/.zshrc:
#       source /path/to/cli_formatter.sh
# =============================================================================

CLI_FORMATTER_MAX_LEN=${CLI_FORMATTER_MAX_LEN:-80}
CLI_FORMATTER_INDENT=${CLI_FORMATTER_INDENT:-2}

_CF_RESET='\033[0m'
_CF_CYAN='\033[0;36m'
_CF_YELLOW='\033[0;33m'
_CF_DIM='\033[2m'

# =============================================================================
# Takes a command as string, returns the multi-line version
# =============================================================================
cmd_format() {
    local cmd="$1"
    local max_len="${CLI_FORMATTER_MAX_LEN}"
    local indent="${CLI_FORMATTER_INDENT}"
    local indent_str
    indent_str=$(printf '%*s' "$indent" '')

    # Poor man tokenization: split on spaces, respecting single/double quotes
    # Uses python3 if available for correct tokenization
    # I used AI here because i sk at python .. Rust anyone?!
    if command -v python3 &>/dev/null; then
        python3 - "$cmd" "$max_len" "$indent_str" <<'PYEOF'
import sys, shlex

cmd      = sys.argv[1]
max_len  = int(sys.argv[2])
indent   = sys.argv[3]

# Skip formatting if shorter than the limit
if len(cmd) <= max_len:
    print(cmd)
    sys.exit(0)

try:
    tokens = shlex.split(cmd)
except ValueError:
    # fallback: simple split
    tokens = cmd.split()

if not tokens:
    print(cmd)
    sys.exit(0)

lines   = []
current = tokens[0]   # first part (the command itself)

for token in tokens[1:]:
    # Append the token to the current line and check if we exceed the limit
    test_line = current + ' ' + token
    if len(test_line) > max_len and current.strip():
        lines.append(current + ' \\')
        current = indent + token
    else:
        current = test_line

lines.append(current)   # last line without backslash

print('\n'.join(lines))
PYEOF
    else
        # standard shell fallback; split on spaces (no complex quoting support)
        local -a tokens
        if [[ -n "$ZSH_VERSION" ]]; then
            read -r -A tokens <<< "$cmd"
        else
            read -r -a tokens <<< "$cmd"
        fi

        if [[ ${#tokens[@]} -eq 0 ]]; then
            echo "$cmd"
            return
        fi

        local current="${tokens[0]}"
        local output=""

        for token in "${tokens[@]:1}"; do
            local test_line="$current $token"
            if (( ${#test_line} > max_len )) && [[ -n "${current// /}" ]]; then
                output+="$current \\\n"
                current="${indent_str}${token}"
            else
                current="$test_line"
            fi
        done
        output+="$current"
        printf "%b" "$output"
    fi
}

# =============================================================================
# BASH, usng the DEBUG hook as a trap
# =============================================================================
if [[ -n "$BASH_VERSION" ]]; then

    _CF_LAST_CMD=""
    _CF_FORMATTED=0

    _cf_preexec() {
        local cmd
        cmd="$(history 1 | sed 's/^[[:space:]]*[0-9]\+[[:space:]]*//')"

        # Avoid double execution
        if [[ "$cmd" == "$_CF_LAST_CMD" && "$_CF_FORMATTED" -eq 1 ]]; then
            return
        fi
        _CF_LAST_CMD="$cmd"
        _CF_FORMATTED=0

        # Ignore short or empty internal commands
        [[ -z "$cmd" ]] && return
        (( ${#cmd} <= CLI_FORMATTER_MAX_LEN )) && return

        local formatted
        formatted="$(cmd_format "$cmd")"

        # Display only if changed (contains newline → actually multi-line)
        if [[ "$formatted" == *$'\n'* ]]; then
            _CF_FORMATTED=1
            echo -e "${_CF_DIM}┌─ Formatted command (>${CLI_FORMATTER_MAX_LEN} chars):${_CF_RESET}"
            echo -e "${_CF_CYAN}${formatted}${_CF_RESET}"
            echo -e "${_CF_DIM}└──────────────────────────────────────────────────${_CF_RESET}"
        fi
    }

    # Install the DEBUG trap
    trap '_cf_preexec' DEBUG

    # Ensure the trap propagates into subshells
    set -o functrace 2>/dev/null || true

fi

# =============================================================================
# ZSH; hook via preexec
# =============================================================================
if [[ -n "$ZSH_VERSION" ]]; then

    autoload -Uz add-zsh-hook 2>/dev/null

    _cf_zsh_preexec() {
        local cmd="$1"

        [[ -z "$cmd" ]] && return
        (( ${#cmd} <= CLI_FORMATTER_MAX_LEN )) && return

        local formatted
        formatted="$(cmd_format "$cmd")"

        if [[ "$formatted" == *$'\n'* ]]; then
            echo -e "${_CF_DIM}┌─ Formatted command (>${CLI_FORMATTER_MAX_LEN} chars):${_CF_RESET}"
            echo -e "${_CF_CYAN}${formatted}${_CF_RESET}"
            echo -e "${_CF_DIM}└──────────────────────────────────────────────────${_CF_RESET}"
        fi
    }

    add-zsh-hook preexec _cf_zsh_preexec

fi

# =============================================================================
# SH / other shells; manual wrapper function: `rx <command>`
# =============================================================================
rx() {
    local cmd="$*"
    if (( ${#cmd} > CLI_FORMATTER_MAX_LEN )); then
        local formatted
        formatted="$(cmd_format "$cmd")"
        if [[ "$formatted" == *$'\n'* ]]; then
            echo -e "${_CF_DIM}┌─ Formatted command:${_CF_RESET}"
            echo -e "${_CF_CYAN}${formatted}${_CF_RESET}"
            echo -e "${_CF_DIM}└────────────────────${_CF_RESET}"
        fi
    fi
    eval "$cmd"
}

# =============================================================================
# Load confirmation
# =============================================================================
echo -e "${_CF_YELLOW}[cli_formatter]${_CF_RESET} active; limit ${_CF_CYAN}${CLI_FORMATTER_MAX_LEN}${_CF_RESET} chars, indent ${_CF_CYAN}${CLI_FORMATTER_INDENT}${_CF_RESET} spaces"
echo -e "  Configuration: ${_CF_DIM}CLI_FORMATTER_MAX_LEN=${CLI_FORMATTER_MAX_LEN} CLI_FORMATTER_INDENT=${CLI_FORMATTER_INDENT}${_CF_RESET}"