CuteTmux

Version · a terminal for your Mac, with ssh and tmux built in

CuteTmux runs your normal login shell (zsh) in glass windows with tabs and splits. Servers can be opened in the same window style, either with tmux (windows and panes come along as tabs and splits) or with a plain ssh shell.

Windows

• Up to 6 windows can be open at once. Each window number (1–6, shown next to the window buttons) remembers its position and size, and its look.
• Drag the window by its top bar. Resize by dragging any edge or corner of the glass (also the glowing border just outside it). Double-click the top bar to zoom. The yellow button (or ⌘M) puts the window into the Dock, the green button enters full screen.
• The palette button (top right) changes the rim color with a click; a right-click opens the background settings (see Look).

Right-click (or press and hold) the Dock icon: the menu lists all open windows with their number and the name of the active tab, a checkmark marks the one in front. Choose one to bring it forward, also a minimized one.

Right-click a folder in Finder → Services: New CuteTmux at Folder opens a new window there, New CuteTmux Tab at Folder adds a tab to the frontmost window instead — the same pair Terminal.app offers.

Type tmux or tmux attach by hand in a plain local tab and CuteTmux offers to switch that window to full tab/pane/session integration, same as a server. A new local window always starts a plain shell, even if a local tmux session is already running elsewhere.

Tabs and splits

Each tab has a small × to close it. Click the name of the active tab to rename it. Without a name of your own, a tab shows the title the program sets, else the running command (for example vim), else the shell name (zsh).

Text, selection and links

• ⌘+ / ⌘− change the font size, ⌘0 resets it. The size is remembered.
• Select text by dragging; double-click selects a word, triple-click a line. Selected text is copied on release. ⌘C copies, ⌘V pastes, ⌘A selects everything. A right-click opens a menu with Copy, Paste and Select All.
• Links: hold ⌘ and the link under the pointer is underlined; ⌘-click opens it (http, https, ftp, file, mailto). Links that wrap over two lines are not joined.
• Programs that use the mouse (btop, vim, tmux inside a shell) receive clicks, drags and the wheel. Hold ⇧ to select text instead.
• The wheel scrolls the history. Typing scrolls back to the bottom.

Servers

Press ⌘S (or Servers… in the app menu) to open the server list. Type to filter, use the arrow keys and Return, or click a server to open it in a new window. Esc closes the list.

• + adds a server, the pencil edits it, the trash can removes it. A server is user@server (a host name or an ssh alias works too). The name is optional.
• While the list is not filtered, your own servers show a number (1–9); press the matching digit key to open that server right away. Drag the handle to reorder them. A server with tmux is shown in green.
• 0 – Local tmux (pinned at the top, not editable or removable): opens a window attached to a local tmux session — the most recently used one if one is already running, or a fresh one if not.
• Use tmux on this server (checkbox): on = tmux control mode; off = a plain ssh shell (marked “ssh only” in the list).
• Hosts from your ~/.ssh/config are listed as well. They cannot be changed; editing one makes a copy of your own and hides the original. CuteTmux never writes to your ssh configuration.
• Your own list is kept in ~/Library/Application Support/CuteTmux/servers and is synced through iCloud with CuteTmux on your iPhone and iPad (same Apple ID, iCloud switched on). Servers you add, edit or delete on one device appear on the others within seconds; the most recently changed list wins. The first time a device syncs, entries that exist only there are kept and added. ssh keys, passwords and the hosts of ~/.ssh/config are not synced.
• Sign-in works as in Terminal: keys, ssh agent, ProxyJump, host key questions and passwords appear in the window. Text in tmux server windows is green; a server without tmux shows white text like a local shell.

Recommended: sign in with ssh keys

For everyday use, ssh keys are much more comfortable than passwords. With a key there is no password prompt: a server window opens straight into the shell, and every new tab of a plain-ssh window connects without asking again. Keys are also safer than passwords.

Set one up once in Terminal (or in a CuteTmux tab):

• Create a key, if you do not have one yet: ssh-keygen -t ed25519 (give it a passphrase; macOS can remember it in the keychain).
• Copy it to the server: ssh-copy-id user@server (asks for the password one last time).
• Check it: ssh user@server should now log in without a password. After that, CuteTmux uses the key automatically, because it calls the normal ssh with your ~/.ssh settings and agent.
• Optional: add AddKeysToAgent yes and UseKeychain yes to a Host * block in ~/.ssh/config so a passphrase is asked only once per login.

Passwords still work: the prompt appears in the window, and CuteTmux stores nothing.

Server windows with tmux

• The server needs tmux installed. CuteTmux attaches to the session cutetmux (or creates it), so what you start survives closing the window or losing the connection.
• Every tmux window is a tab; a split is a tmux split. ⌘T creates a tmux window, ⌘D splits, ⌘W and the tab × close panes and windows on the server. Renaming a tab renames the tmux window. Dragging the divider resizes the pane.
• ⌘⇧S (Sessions…) lists the tmux sessions on the server, with the number of windows, attached clients and last activity; while not filtered, sessions are numbered too and a digit key switches to that one. Choose one to switch, + for a new session, the trash can to kill one.
• If the connection cannot be made, or tmux is missing, the window stays open and shows the reason (for example No route to host or tmux: command not found). Close it with ⌘W.

Servers without tmux

A window for a server with the tmux checkbox off runs ssh user@server in every tab. Tabs are independent connections, named after the server. When a connection ends, the tab stays with the message “Connection closed” until you close it.

Look

• Click the palette button: the next rim color. The background color follows the rim.
• Right-click the palette button for the background settings of this window:
  • Background color – eight colors; the rim color is selected at first. Tick Follow rim color to keep the background and the prompt following it.
  • Color strength – how strongly the color fills the glass (default 30 %, 0 % = plain dark glass).
  • Transparency – how see-through the window is (default 5 %). Text stays sharp.
  • Prompt color – the shell prompt at the start of a line (for example ralf@Mac ~ %) is drawn in the rim color by default, also over ssh and in tmux. Pick another color, or untick Color the prompt to switch it off. Prompts that already use colors of their own are left alone.
  • Reset – back to the defaults.
• On a light background, text and cursor turn black so they stay readable.
• Position, size and look are stored per window number.

Menu shortcuts

Troubleshooting

• “No route to host” for a server in your local network: allow CuteTmux under System Settings › Privacy & Security › Local Network, then restart the app. If ssh in Terminal works but CuteTmux does not, this is the cause.
• “tmux: command not found”: install tmux on the server (for example apt install tmux), or untick Use tmux on this server.
• Passwords: the ssh password prompt appears in the window; nothing is stored by CuteTmux.
• Contact: cutetmux@neumann-edv.de