Termius

Termius is the SSH client on Cole’s phone, the counterpart of Ghostty on the desk. With Tailscale running on the phone, it reaches the Mac mini and every server by name, attaches to the tmux session where an agent is working, and lets you answer its question from wherever you are. Several of Cole’s tmux bindings exist mainly so that this is pleasant on a touch keyboard.

What Termius is

Termius is a cross-platform SSH client for iOS, Android, macOS, Windows and Linux. Beyond SSH it connects with Mosh, Telnet and serial, browses files over SFTP, forwards ports, and keeps saved hosts, keys and snippets in a vault. For reaching machines it has the features you would expect from a desktop client: keys imported into its keychain, agent forwarding through its own built-in agent, and “host chains” that hop through one or more jump hosts in one tap.

The free Starter plan covers the core, with a local vault, SSH, SFTP and port forwarding. Pro ($10 per month billed annually (as of Oct 28, 2026, termius.com)) adds a personal cloud vault that syncs hosts and keys across your phone and computers, session logs and snippet automation. Team and Business plans add shared vaults.

A real terminal on a phone

The mobile app is built around the fact that a phone has no Ctrl key:

• An extra key row. A keyboard add-on above the system keyboard holds Ctrl, Esc, Tab, arrow keys, function keys and symbols, in groups of four that you can reorder and customize. The first three groups ride along above the keyboard; the rest live in a side panel.
• Gestures. Long-press and drag to send arrow keys (the farther you drag, the faster), double-tap for Tab, pinch to resize the text.
• Volume buttons. Each one can be assigned an action, such as a key you press often.
• Snippets and history. Saved commands and earlier ones, a tap away in the side panel.
• Voice typing. Dictate a command or a prompt in the keyboard’s AI panel.

How Cole’s setup meets the phone halfway

A phone keyboard makes chords expensive: every modifier is an extra tap, often on another row. Cole’s tmux keymap takes that seriously.

• One-chord movement. Alt+h and Alt+l move between windows, Alt+s cycles sessions, Alt+1 to Alt+9 jump straight to a window. The config marks the first two “mobile-friendly”.
• Control keys as plain letters. Once the prefix is reachable, prefix k sends Ctrl-C, prefix q sends Ctrl-D, prefix z sends Ctrl-Z and prefix l sends Ctrl-L, so interrupting an agent or clearing the screen needs no more modifiers.
• The scroll direction. When a Termius update flipped which wheel events a finger swipe sends, tmux started scrolling the wrong way. Rather than relearn, Cole re-inverted tmux’s wheel bindings so a finger-up swipe again reveals older output.
• A picker that fits. After connecting, tm lists every tmux session in an fzf menu sized to the screen, most recent first (tm, the Session Picker).
• A dashboard that fits. A login dashboard like Cole’s porchlight has a compact layout at phone width and renders from cache in milliseconds, so the first screen after logging in already says which agents are waiting.

A typical check-in

1. Open Termius and tap the Mac mini (or a server). Tailscale makes the name resolve from anywhere, with no port open on the internet.
2. Type tm and pick the session, or tl for the last one.
3. Alt+l through the windows. The status line colors show which agents are working (green) and which went quiet.
4. Answer the agent’s question, or dictate a longer instruction, then put the phone away. Everything keeps running in tmux.

Gotchas

• Phones drop connections. Switching apps, losing signal or locking the screen can end the SSH session. With everything inside tmux nothing is lost: reconnect and tl. Mosh, which Termius supports, survives network changes better than SSH, at the cost of needing a server-side install.
• Keys, not passwords. Generate or import a key in Termius’s keychain and add its public half to each machine’s authorized_keys. Cole’s servers accept keys only (see SSH).
• Mind the clipboard. Copying a long agent transcript on a phone is awkward. Cole’s tmux binding Alt+c captures a pane’s whole history into a tmux buffer, which is easier to paste somewhere else from inside tmux.
• Small screens, long lines. A narrow terminal wraps everything. Cole’s prompt puts the cursor on its own line so a long path does not squeeze the command you type.

The desktop half of the pair is Ghostty, and the Tailscale page covers the network that makes the phone a peer of every other machine.