open

cyber-mux open [--launch <cmd>] [--template <name>] [--cwd <path>] [--at <placement>] [--env <KEY=VALUE>...] [--label <name>]

Open a new pane and launch a command in it. Prints the new pane’s id, and its workspace when the backend bound one (null otherwise).

• --launch <cmd> — command line to run in the new pane; omit for a blank pane.

• --template <name> — build a whole named pool in the opened space instead of a single pane, from a resolvable template. Resolved and validated before anything opens, so a typo in the name leaves nothing behind. Conflicts with both --launch and --env (a template owns everything in the panes it declares); rejected by commander (exit 2) if combined with either.

• --cwd <path> — working directory for the new pane; defaults to the caller’s own cwd.

• --at <placement> — one of pane:right, pane:down, pane:float, tab (default), or workspace. workspace is the backend’s own visible space (herdr workspace create, tmux a new window) — never a detached tmux session, which would be invisible to focus. pane:float opens a floating pane — one that sits above the tiled layout rather than taking a share of it, so nothing else is resized. It is the one placement that is not universal: tmux 3.7+ (new-pane) and zellij (new-pane --floating) open a real one, while wezterm and herdr have no such concept and refuse it with backend-unsupported (exit 1) rather than quietly substituting a split. The value is always accepted by the flag — which backend can realize it is a runtime answer.

• --env <KEY=VALUE> — repeatable; sets each variable natively at the pane’s birth.

• --label <name> — names whatever --at opened, at whatever tier it opened it:

  --at	herdr	tmux
  workspace	workspace label	window name
  tab	tab label	window name (workspace and tab are both a Window here)
  pane:right / pane:down / pane:float	pane label	pane title

  Omit it and each backend keeps its own default.

See also worktree add and template, which share --template/--at/--env/--label.

Examples

# Blank pane, split to the right of the caller
cyber-mux open --at pane:right

# A floating pane above the layout — tmux 3.7+ or zellij; refused elsewhere
cyber-mux open --at pane:float --launch "watch -n5 git status"

# Launch a command in a new tab, in a specific directory
cyber-mux open --launch "npm run dev" --cwd ~/code/my-app --at tab

# A labeled workspace with an env var set at birth
cyber-mux open --at workspace --label logs --env LOG_LEVEL=debug --launch "tail -f app.log"

# Build a whole pane pool from a template
cyber-mux open --template pool-4 --cwd ~/code/my-app