Tmux (No Windows)

No TTY: Never attach or type directly in tmux. Always interact via send-keys and read output with capture-pane.

Policy

• •Use tmux only when a command is interactive or long-running and Codex must read stdout/stderr (e.g., SSH, REPLs, tailing logs).
• •Always create a new session for a task; prefer a unique name like codex-<task> or codex-<timestamp>.
• •Never create or switch windows (new-window, select-window, kill-window, rename-window).
• •Use panes only within the single default window.
• •Interact via tmux CLI commands (send-keys, capture-pane, select-pane).
• •Use tmux key sequences via send-keys (e.g., C-c, C-m) instead of typing them in a TTY.

Core workflow

1. •

   Create a session:

   • •tmux new-session -d -s <name>
   • •If unsure whether it exists, use tmux has-session -t <name>.
2. •

   Run a command in the first pane:

   • •tmux send-keys -t <name>:0.0 "<command>" C-m
3. •

   Read output (stdout/stderr):

   • •tmux capture-pane -pt <name>:0.0 -S -200 (adjust -S for more scrollback)
4. •

   Interact further:

   • •tmux send-keys -t <name>:0.0 "<input>" C-m

Working with panes

• •Split vertically:
  • •tmux split-window -v -t <name>:0.0
• •Split horizontally:
  • •tmux split-window -h -t <name>:0.0
• •Select a pane:
  • •tmux select-pane -t <name>:0.<pane>
• •Run a command in a pane:
  • •tmux send-keys -t <name>:0.<pane> "<command>" C-m
• •Capture output from a pane:
  • •tmux capture-pane -pt <name>:0.<pane> -S -200

SSH example

• •tmux new-session -d -s codex-ssh
• •tmux send-keys -t codex-ssh:0.0 "ssh user@host" C-m
• •tmux capture-pane -pt codex-ssh:0.0 -S -200

Cleanup

• •Kill the session when done:
  • •tmux kill-session -t <name>

CLI tips (no TTY)

• •Check if a session exists:
  • •tmux has-session -t <name>
• •List sessions/panes:
  • •tmux list-sessions
  • •tmux list-panes -t <name>
• •Stop a running command:
  • •tmux send-keys -t <name>:0.<pane> C-c
• •Send literal text (avoid shell expansion surprises):
  • •tmux send-keys -t <name>:0.<pane> -l \"literal text\"
• •Capture full scrollback when debugging:
  • •tmux capture-pane -pt <name>:0.<pane> -S -
• •Do not use tmux attach; rely on CLI commands only.