Terminal Triggers in Electerm: Let the Terminal Answer Itself

Some prompts never change. The Cisco pager says --More-- for the hundredth time. scp asks are you sure you want to continue connecting (yes/no)? on every new host. A long show running-config stops every page and waits for a spacebar you are tired of pressing.

Electerm triggers automate exactly that layer: they watch the decoded terminal output stream, match text or regular expressions, and send a response back into the session — a space, a y, an Enter, or just a desktop notification. Think ZOC's auto-respond, built into every terminal tab.

Read this first: a trigger sends real input to a real machine. An over-broad rule like "reply y to anything containing ?" will eventually confirm something you did not mean. The safety section at the bottom is not optional reading.

1. The three levels, side by side

A trigger rule always has the same shape — a name, a match, an action, and a firing mode (details in section 3). What differs is where the rule lives, and that decides who it applies to and whether it is saved:

	Global (predefined)	Bookmark	This session
Where	Settings → triggers	Bookmark edit form → triggers tab	Footer's ƒx icon → This session tab
Applies to	Every terminal tab (unless muted for one)	Every session opened from that bookmark	Only the current tab, right now
Saved?	Yes — persisted in the database and synced	Yes — stored on the bookmark record	No — in-memory only, gone when the tab closes
Best for	Pagers, confirmations, disconnect notices you always want	Logins and prompts specific to one host or role	One-off experiments before committing to a saved rule

The footer shows the whole picture: the ƒx icon in the footer carries a badge with the number of effective triggers for the current tab. Click it and a popup opens with two tabs — Global (every predefined rule, switches flip the persisted on/off default) and This session (everything active here, switches muted per-session only). Creating and editing predefined rules happens in the Settings panel; the popup is for switching and for temporary rules.

Effective triggers for a tab = global rules (resolved with your per-session on/off overrides) + that tab's session rules. Only predefined rules persist; bookmark rules stay on the bookmark; session temp rules live on the in-memory tab.

2. A first trigger in 60 seconds

1. Open Settings → triggers, click New (or pick from Presets).
2. Name it Cisco pager, match type Text, value --More--.
3. Action Send text, value a single space, Send Enter off, mode Every new match + cooldown, cooldown 500 ms.
4. Save, then open a session and run something that pages. Each --More-- is answered with a space, hands-free.

Prefer JSON? The editor has a JSON button — paste an array of rules, invalid regex or a missing match is rejected with an explanation:

[
  {
    "name": "Cisco pager: --More--",
    "enabled": true,
    "match": { "type": "text", "value": "--More--", "caseSensitive": false },
    "action": { "type": "send", "value": " " },
    "sendEnter": false,
    "mode": "cooldown",
    "cooldownMs": 500
  }
]

3. How a rule works

Every rule is five decisions:

• Match — Text (a literal string, special characters are escaped for you) or RegExp (a raw JavaScript regular expression). Matching is case-insensitive by default; flip the case-sensitive switch when Password: and password: must be told apart. ANSI colour codes are stripped and carriage returns normalised before matching, so coloured prompts still match, and a match split across two network chunks still fires.
• Action — Send text writes into the session; Notify only shows a desktop notification with the matched snippet and sends nothing. Notify is the right answer for sudo password prompts: you want to be told, not auto-type a secret.
• Send Enter — on by default, the payload gets a trailing carriage return unless it already ends with \r or \n. Turn it off for single-key answers like a pager space. The send text supports escapes: \n \t \r \\ \xHH hex bytes and ^X caret notation (^M is Enter, ^C is Ctrl-C).
• Mode — Every new match + cooldown (default, each new occurrence fires but at most once per cooldown interval), Every new match (no throttling), or Once per session (fires a single time, e.g. accepting a new SSH host key with yes).
• Enabled — a per-rule switch, plus per-session overrides: muting a global rule in the footer popup affects only the current tab and is not persisted.

Two engine guarantees are worth knowing. First, a newly enabled or edited rule ignores buffered history — it only reacts to output that arrives after the change, so turning a rule on never replays yesterday's scrollback. Second, cooldown consumes the suppressed occurrence — a greedy regex anchored in old output cannot grow into later chunks and be mistaken for a fresh match.

4. Eight presets worth stealing

Settings → triggers → Presets ships eight starting points. They are ordinary rules — pick one, then edit the match or the reply to fit your hosts:

Preset	Match	Reply
Cisco pager: --More--	text --More--	space, no Enter
Pager: press any key to continue	regex press any key|press .* to continue	space, no Enter
Confirm: Are you sure? [y/n]	regex are you sure.*\[y/n\]|confirm.*\(y/n\)	y + Enter
Overwrite confirm: Overwrite? (y/n)	regex overwrite.*\(y/n\)	y + Enter
sudo password prompt → notify	regex \[sudo\]\s*password	notification only
SSH new host key → accept once	regex are you sure you want to continue connecting	yes + Enter, once per session
Telnet login: auto username	regex login[: ]*$|username[: ]*$	your username + Enter (fill it in)
Connection closed → notify	regex connection (closed|reset|refused)|lost connection	notification only

5. Recipes

Page through anything hands-free — the Cisco preset, or generalise the pager preset to --More-- |\(END\)|--More-- if you live in less and journalctl too.

Accept the host key on a fleet rollout — SSH-new-host-key preset in once mode. It answers yes to the first prompt and can never fire again in that session, so a later man-in-the-middle prompt is not auto-accepted.

Get tapped on the shoulder by sudo — the sudo preset with Notify only. The notification carries the last ~240 characters of matched output, so you see which tab needs you. Never auto-send a password: it lands in logs, in scrollback, in screen shares.

Fill a telnet username, nothing more — telnet-login preset answers the login: prompt with the username and Enter, but leaves the password prompt to you (pair it with a notify rule on password:).

Watch for drops during a long migration — connection-closed preset with Notify only and a 5 s cooldown. One toast per incident instead of a toast per chunk.

Per-host login flows — put the rule on the bookmark, not globally. A core switch that asks Username: and a Linux box that asks login: need different answers; bookmark triggers keep them from leaking into each other.

Trying something risky? Prototype it as a This session rule from the footer popup. It dies with the tab. Promote it to global or bookmark only after watching it behave.

6. Safety rules that actually matter

Auto-answer is a loaded tool. Five habits keep it safe:

1. Anchor your regex. .*y/n.* matches half the manual page. Prefer are you sure.*\[y/n\] — specific enough to fire on the prompt and nothing else.
2. Prefer once and cooldown over repeat. repeat with no throttle re-sends on every new occurrence; a prompt loop can spiral into dozens of answers per second.
3. Notify, don't send, for secrets and destruction. Passwords, rm -rf, drop table, reboot — if the cost of a wrong answer is high, the trigger should tap your shoulder, not press Enter.
4. Mute per session, don't delete globally. Debugging one host that echoes oddly? Flip the rule off in the footer popup's This-session tab. The global default — and every other tab — stays untouched.
5. Test in a scratch tab first. Session rules are free and disposable. Watch one real prompt cycle before the rule graduates to Settings or a bookmark.

7. Combining with the rest of electerm

• Quick commands send one reply on demand; triggers send it automatically. If you find yourself clicking the same quick command at the same prompt every day, that click wants to become a trigger.
• Batch input / mirror input drive many hosts at once; triggers answer what those hosts ask back. Mirror a command across four nodes, let a pager trigger dismiss --More-- on all four.
• Bookmark triggers travel with the bookmark through sync, so the login flow you tuned on the laptop is already correct on the desktop.

Cheat-sheet

• A trigger = match (text or regex, case-insensitive by default, ANSI stripped) → action (send text or notify) → mode (cooldown / every match / once per session).
• Three homes: global (Settings, persisted, synced), bookmark (travels with the host), this session (footer ƒx, in-memory only).
• Footer ƒx badge = effective trigger count for the current tab. Global tab flips the saved default; This-session tab mutes per tab.
• Send text supports \n \t \r \\ \xHH ^X; Enter is appended unless the text already ends with a newline or you switch it off.
• Rule of thumb: routine keypress → send, secret or destructive → notify, unsure → session-only first.

Next: SSH in Electerm for the sessions your triggers will live in, or Batch and Mirror Input for driving many terminals at once.