synsh

The AI-native shell. Type a command like any shell — or just say what you want, and it asks synapd. Start it with synsh, or make it your login shell with chsh -s /usr/bin/synsh — it is already in /etc/shells.

⚡ AI online — type naturally or use shell commands

If the banner doesn't say AI online, synapd isn't reachable: check systemctl status synapd and that the model is in /var/lib/synapd/models/synapse.gguf.

Language

synsh says everything in fourteen languages and understands requests in all fourteen whatever it is set to — the phrase tables hold every language at once, so somebody working in German who types list files out of habit still gets it, and accents are optional in both directions (wie spaet ist es, que hora es).

It follows the language the image was booted in and needs no configuration. syn lang says which one; synsh --lang de changes it for one run, and set language de in ~/.synshrc for good.

⚠ The catalog is compiled in, not gettext. synsh is on the ISO and runs before /usr is necessarily complete, and a shell that cannot find its .mo files must still be able to say why it cannot. The 91 messages, the English text and every catalog's shape are generated from one list, so a message cannot exist in one place and not another, and a translation cannot slide onto the wrong id.

⛔ What the language changes is what it says, never what it runs. ls is ls in every language and so is every exit code — synsh --lang ja -c 'false' still exits 1. The language codes it lists (en de fr …) are tags you type, not words, and stay as they are.

Shell features

Real GNU readline (line editing, history), aliases, built-ins that work outside the REPL, redirection and pipes for built-ins, and command lists — ;, &&, ||.

Several of those are more recent than you'd expect, because they were quietly broken:

• Aliases were never expanded at all until pkgrel 8.
• readline was a phantom dependency — declared but never actually linked, so you got no line editing. Genuinely enabled in pkgrel 7.
• Built-ins didn't work outside the REPL and couldn't redirect or pipe.

Colour output

synsh used to emit colour unconditionally: --no-color was dead code, and the escape sequences leaked into pipes, corrupting anything that parsed its output. Fixed in pkgrel 6 (9681fa6).

If you see escape codes in a pipeline, you are running something older than pkgrel 6.

⚠️ synsh has two incompatible tokenizers

This is the single most important thing to know before touching the parser. A change to quoting, splitting or expansion must be made in both or you get behaviour that differs between code paths — and the divergence is silent.

Terminal setup

New in 0.2.5. On 0.2.4 and earlier, and on any system installed from one, the default terminal is foot — nothing rewrites a user's synuirc on upgrade, so an upgraded machine keeps whatever it already had.

The default terminal is kitty. foot is kept as the rescue terminal and is still installed: it is 793 KiB against kitty's 65 MiB, and it renders on the CPU where kitty needs working OpenGL — which is what you want in a VM on llvmpipe, or when a GPU driver has just broken. It is second in every fallback chain, and systems installed before the switch still have it as their default.

Change it with terminal = <name> in ~/.config/synui/synuirc.

kitty's transparency needs dynamic_background_opacity yes set from its FIRST launch. kitty's own documentation is explicit that the option cannot be enabled by reloading the config, and that a background_opacity change on reload only works if dynamic opacity was already on when kitty started. A kitty.conf shipped without it leaves the transparency slider permanently inert for that install, and writing the setting afterwards does not repair it — kitty has to be restarted.

Both terminals' configs are generated in more than one place (live ISO, installed user, packaged default); if you change one, change them all.

A past failure worth recognising: foot silently refused its own config because [cursor].color had been removed upstream. The symptom was a terminal that came up with default colours and no explanation.

See also: synapd, Troubleshooting.