The login command

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login is the terminal client for signing in. It collects an identifier, renders whatever credential prompts the authority sends, installs the token it is granted, and replaces itself with your shell.

login [name] [options]
login --try <name> [options]
login --try-no-password <name> [options]

It does not know what a password is. It renders the prompts it is asked to render and returns the answers, so adding a new credential type — a one-time code, a smartcard — changes the authority and leaves login alone.

Naming a principal, or not #

With no name, login asks for one:

Username: alice
Logging in as alice
Password:

With a name, the first prompt is skipped. The Logging in as line comes from the authority rather than from login, so it will gain a realm once authorities have them.

A principal who needs no credential is signed in immediately, with no prompt at all — see passwordless accounts.

--try and --try-no-password #

Both attempt a named principal and fall back to an ordinary prompt rather than failing. They differ in what they offer to collect.

--try <name> attempts the principal with login's full capabilities. A principal whose policy requires no credential is signed in immediately; one whose policy calls for a password is prompted for it.

--try-no-password <name> attempts the principal while declaring that it can collect nothing, so only a principal who needs no credential can succeed. This is what a console autologon uses.

Neither flag asserts that anyone is authenticated. The authority still decides, and understating what you can collect only denies you prompts you could have rendered — so running either by hand gains you nothing you did not already have.

The first two columns below describe credential policy, not just whether a password is stored. They assume an enabled account with console logon permitted and, for password sign-in, a password set.

A fallback restarts the sign-in from Username:, so you are never locked to the principal that was attempted.

When a fallback explains itself #

login says why it fell back only if something was already on your terminal.

A --try that reached a password prompt has interrupted you, and dropping to Username: without a word would read as a fault — you typed a password and got asked for a name. So it reports first:

$ login --try alice
Logging in as alice
Password:
login: Password incorrect
Username:

A --try-no-password that was refused before anything was rendered has interrupted nobody, and stays quiet. That is what keeps a line about a failed autologon off the console of every machine where the principal requires a credential.

Falling back is limited to denials another principal could survive. A failure of the authority itself is reported and login exits, because offering a prompt that cannot work either would spin a console.

Where existence is checked #

login asks /run/ident.sock whether a principal exists, not the logon socket. The logon socket will not tell it — an authority never distinguishes an unknown principal from a bad credential — while the identity socket answers plainly, which is what it is for.

If that lookup cannot be answered, login attempts the sign-in anyway rather than reporting an absence. An unreachable source reported as "no such user" would turn an outage into a fact.

Autologon on a console #

A console that signs in on its own is a passwordless principal plus --try-no-password. On a live image, peinit starts:

/bin/login --console --try-no-password peios

The same service definition suits an image where peios requires a password: the attempt is refused before anything is rendered, and an ordinary prompt appears. No second seed, and no conditional configuration.

To require a password instead of autologon, first set the principal's password with lps password, then select lps policy <name> password. Setting the password alone leaves the none credential policy and autologon unchanged.

Taking --try-no-password out of the login-console service's Arguments stops the automatic attempt, but does not change the account's credential policy: a principal whose policy is still none can still sign in at that prompt without a credential. To move the prompt to another terminal, change the service's TTYPath — see controlling services.

System Settings chooses it in its Startup & Shutdown section, under Console Sign-In: Automatic Sign-In is Off, or one of the local accounts. The choice is written the moment it is made, as Arguments: --console, followed by --try-no-password and the account if one is chosen. It applies the next time login-console starts, at the latest the next boot. Changing it needs write access to Machine\System\Services\login-console, which as shipped only Administrators have.

GXWI information on the console #

Managed login --console sessions show GXWI's browser address and certificate SHA-256 fingerprint before authentication when GXWI is installed. Compare the fingerprint on this trusted local console with the browser's certificate details before accepting its warning. See the machine's certificate.

The banner reads /var/state/gxwi/certificate.sha256 and the configured Machine\Software\GXWI\Listen address and port. With the IPv4 wildcard listener Peios ships (0.0.0.0:7780), it lists the machine's active non-loopback IPv4 addresses. If the value is missing or unreadable, the banner shows GXWI's own fallback, the loopback address 127.0.0.1:7780. An IPv6 wildcard lists IPv6 addresses; link-local addresses that need an interface zone are omitted. A specific listen address is displayed as configured. This is connection information, not a check that GXWI is currently running.

Information is read once each time login starts. Missing or malformed fingerprints and unavailable addresses are reported without preventing login. Ordinary login invocations without --console do not show this banner.

Options #

-f is not implemented. On Linux it means "trust me, they are already authenticated", gated only by the caller being root. On Peios that decision belongs to the authority, taken from the verified peer, so accepting a flag here would put an authentication bypass in an unprivileged process.

The environment your shell starts in #

Without -p, login builds a fresh environment: HOME, SHELL, USER, LOGNAME, PATH=/bin, and TERM. The shell's argv[0] gets a leading dash, which every shell reads as "this is a login shell, run the profile files".

TERM is carried through if login was started with one. Otherwise login decides it from the terminal it is on, the way a getty does elsewhere: linux on a virtual console (/dev/tty1 and its siblings, the display), vt220 on anything else (a serial line, a hypervisor's paravirtual console). /dev/console is whichever of those the kernel chose, and login resolves it through the kernel's own record of the active console rather than guessing, so one service definition on /dev/console gets the right answer on a machine with a display and on one without.

The home directory comes from the profile the authority sent, and a missing one is not fatal. login reports it and starts you in /. Refusing to proceed over an absent directory would turn a cosmetic problem into being locked out.

login does not create it. Two reasons, and either would be enough. It has already made your token its own by the time it changes directory, so it is you rather than the system — and /home lets you walk through it but not create in it. And directory provisioning has no business inside the one program that has to keep working when everything else is broken. The authority creates the directory when it grants the logon, before login is handed anything; reaching this fallback means the authority named no home, or could not make one.

Exit status #

login does not return on success — it replaces itself with your shell, so what you see afterwards is the shell's exit status.

Multiple local consoles #

The Experimental edition provides independent login sessions on tty1, tty2 and tty3. Switch between them with Alt+F1, Alt+F2 and Alt+F3 at a text console, or use chvt 1, chvt 2 and chvt 3 with the required console authority. Switching does not lock or log out the session you leave.

login-console follows the kernel's primary console: peinit resolves a display console to the fixed tty1, or uses the selected serial/paravirtual terminal. It retains the live-medium passwordless peios attempt. Additional services login-tty1, login-tty2 and login-tty3 show ordinary username prompts. On a display-primary machine, the duplicate login-tty1 service is skipped because login-console already owns that terminal. On a serial-primary machine all three local prompts can run alongside the serial session. Missing terminals are skipped.

First-boot setup retains the primary console. Additional terminals wait until both setup service definitions have been removed; they collect no credentials while setup is pending. Logging out terminates that terminal service's remaining processes and produces a fresh prompt with canonical input and echo restored. A normal logout does not consume the crash-restart budget. This resets terminal input settings; it does not implement a session lock or promise to erase all screen history.

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