Type Safer Commands on a Phone: The Compose Bar, Autocomplete and Dangerous-Command Check

The problem

On a phone, typing directly into a live shell is risky. Autocorrect is off, the keyboard is small, and a missing space turns rm -rf /var/www/old into something very different. By the time you notice, Return has been pressed. Nothing on a stock SSH terminal stops you.

The compose bar

The compose bar is a chat-style box above the keyboard. You tap the chat button on the keyboard toolbar to open it, write the whole command, check it and send it as one line. Tap the keyboard button to go back to raw keys for things like vim and Ctrl-C.

Inside it:

• Ghost-text autocomplete: grey text shows the likely rest of the command, based on your recent command history first, then a built-in set of about 55 common commands and their options. Tap the suggestion to accept it. Suggestion chips scroll above the box.
• A check before sending: if the command looks destructive, you see “Run this command?” with the reason and Send Anyway or Cancel.

What counts as risky

The check looks for patterns such as:

• rm -rf on any target
• mkfs, and dd writing to a device
• Piping curl into a shell
• Fork bombs
• Shutdown or reboot commands
• iptables -F
• find ... -delete

It works through sudo and env prefixes and checks each part of a command chained with ;, | or &&.

Be clear about the limit

This is a safety net, not a guarantee. It recognises known patterns. A harmful command written another way won’t be flagged, and an innocent-looking one may be. It applies only to what you send from the compose bar, not to keys you type straight into the terminal. Treat it as a speed bump that catches typing mistakes.

Premium extras

With Premium, the + menu lets you attach a photo, take a picture, choose a file or paste an image. The file is uploaded to a temporary folder on the server over SFTP and its path is added to your message, which is useful for handing screenshots to a CLI agent. A microphone button dictates commands, using on-device speech recognition when available.

A good habit

For anything destructive, write it in the compose bar, read it once, then send.

FAQ

Which commands trigger the warning? Commands like rm -rf on any target, mkfs, dd writing to a device, piping curl into a shell, fork bombs, shutdown or reboot, iptables -F and find -delete.

Does it stop me running them? No. It asks “Run this command?” with the reason, and you can choose Send Anyway or Cancel.

Does the check apply when I type straight into the terminal? No. It covers commands sent from the compose bar only.

What does Premium add here? Attaching photos or files and dictating commands by voice.