start: tmux + claude code

start.sh

#!/usr/bin/env bash
# start — tmux dev session manager
# Creates a split-pane dev layout: claude | shell / git-status watch
# Pure Bash version (no dependencies beyond tmux + fzf)

set -euo pipefail

# ── Helpers ──────────────────────────────────────────────────────────────────

sanitize_session_name() {
  echo "${1//[.:]/_}"
}

list_sessions() {
  local prefix="$1"
  tmux list-sessions -F '#{session_name}	#{session_windows}' 2>/dev/null \
    | awk -F'\t' -v p="$prefix" '$1 ~ "^"p { print $1 "\t" $2 }'
}

next_session_name() {
  local base="$1"
  if ! tmux has-session -t "$base" 2>/dev/null; then
    echo "$base"
    return
  fi
  local i=2
  while tmux has-session -t "${base}-${i}" 2>/dev/null; do
    ((i++))
  done
  echo "${base}-${i}"
}

create_session() {
  local name="$1"
  tmux new-session -d -s "$name" -n main
  tmux send-keys -t "$name" "claude" C-m
  tmux split-window -h -t "$name"
  tmux split-window -v -t "$name"
  tmux send-keys -t "$name" "watch -n 1 git status" C-m
  tmux select-pane -t "$name:0.0"
}

attach_session() {
  exec tmux attach -t "$1"
}

# ── Main ─────────────────────────────────────────────────────────────────────

if ! command -v tmux &>/dev/null; then
  echo "error: tmux not found" >&2
  exit 1
fi

base="dev-$(sanitize_session_name "$(basename "$PWD")")"

# --new / -n: skip picker, create new session directly
if [[ "${1:-}" == "--new" || "${1:-}" == "-n" ]]; then
  name=$(next_session_name "$base")
  create_session "$name"
  attach_session "$name"
fi

# Read existing sessions into arrays
names=()
descs=()
while IFS=$'\t' read -r sname windows; do
  names+=("$sname")
  if [[ "$windows" == 1 ]]; then
    descs+=("$sname — 1 window")
  else
    descs+=("$sname — $windows windows")
  fi
done < <(list_sessions "$base")

# No existing sessions: create one directly
if [[ ${#names[@]} -eq 0 ]]; then
  create_session "$base"
  attach_session "$base"
fi

# Build fzf picker
descs+=("+ New session — Create a new dev session")
descs+=("+ New session (kill others) — Create new session and kill all others")

if ! command -v fzf &>/dev/null; then
  # Fallback: simple select menu if fzf isn't available
  echo "start — pick a session:" >&2
  for i in "${!descs[@]}"; do
    printf "  %d) %s\n" "$((i + 1))" "${descs[$i]}" >&2
  done
  printf "Choose [1-%d]: " "${#descs[@]}" >&2
  read -r choice
  if [[ -z "$choice" ]] || ! [[ "$choice" =~ ^[0-9]+$ ]] \
      || ((choice < 1 || choice > ${#descs[@]})); then
    exit 0
  fi
  idx=$((choice - 1))
else
  selection=$(printf '%s\n' "${descs[@]}" | fzf --height=~20 --reverse \
    --header="start" --prompt="session> " \
    --color="header:magenta,pointer:magenta,prompt:magenta") || exit 0
  # Find index of selected item
  idx=-1
  for i in "${!descs[@]}"; do
    if [[ "${descs[$i]}" == "$selection" ]]; then
      idx=$i
      break
    fi
  done
  [[ $idx -eq -1 ]] && exit 0
fi

total=${#descs[@]}
new_idx=$((total - 2))
kill_idx=$((total - 1))

if [[ $idx -eq $kill_idx ]]; then
  # Kill all existing sessions and start fresh
  for sname in "${names[@]}"; do
    tmux kill-session -t "$sname" 2>/dev/null || true
  done
  create_session "$base"
  attach_session "$base"
elif [[ $idx -eq $new_idx ]]; then
  name=$(next_session_name "$base")
  create_session "$name"
  attach_session "$name"
else
  attach_session "${names[$idx]}"
fi