EXIT(1POSIX)

💖 EXIT(1POSIX) 💖

okay bestie, so this little icon lives in the POSIX Programmer's Manual — like, that's the manual name, and this page is EXIT(1POSIX). But real talk before we even start:

🌸 PROLOG 🌸

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

Like... heads up. Don't come for me if Linux is doing its own thing. It literally says so right there. 🙈

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✨ NAME ✨

exit — cause the shell to exit

🦋 SYNOPSIS 🦋

exit [n]

💅 DESCRIPTION 💅

The exit utility shall cause the shell to exit from its current execution environment with the exit status specified by the unsigned decimal integer n. If the current execution environment is a subshell environment, the shell shall exit from the subshell environment with the specified exit status and continue in the environment from which that subshell environment was invoked; otherwise, the shell utility shall terminate with the specified exit status. If n is specified, but its value is not between 0 and 255 inclusively, the exit status is undefined.

no cap, undefined is the scary one. do not test it.

A trap on EXIT shall be executed before the shell terminates, except when the exit utility is invoked in that trap itself, in which case the shell shall exit immediately.

So like — your EXIT trap gets its little moment ✨ before the shell dips. But if you call exit from inside that very trap? It's over. Immediately. No encore. 💀

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🎀 OPTIONS 🎀

None.

(Yeah. Zero. Not a single flag. She's simple, she's iconic, she doesn't need options. 👑)

🍓 OPERANDS 🍓

See the DESCRIPTION.

🌈 STDIN 🌈

Not used.

💜 INPUT FILES 💜

None.

🧚 ENVIRONMENT VARIABLES 🧚

None.

⭐ ASYNCHRONOUS EVENTS ⭐

Default.

🌸 STDOUT 🌸

Not used.

🩷 STDERR 🩷

The standard error shall be used only for diagnostic messages.

🦋 OUTPUT FILES 🦋

None.

✨ EXTENDED DESCRIPTION ✨

None.

💖 EXIT STATUS 💖

The exit status shall be n, if specified, except that the behavior is unspecified if n is not an unsigned decimal integer or is greater than 255. Otherwise, the value shall be the exit value of the last command executed, or zero if no command was executed. When exit is executed in a trap action, the last command is considered to be the command that executed immediately preceding the trap action.

lowkey important: "the last command" inside a trap = the command that ran right before the trap fired. Not the trap itself. periodt.

💀 CONSEQUENCES OF ERRORS 💀

Default.

The following sections are informative.

🫶 APPLICATION USAGE 🫶

None.

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🌟 EXAMPLES 🌟

Exit with a true value:

exit 0

Exit with a false value:

exit 1

Propagate error handling from within a subshell:

(
    command1 || exit 1
    command2 || exit 1
    exec command3
) > outputfile || exit 1
echo "outputfile created successfully"

the way that subshell just handles its business and reports back... we love a self-sufficient queen 🫶

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👑 RATIONALE 👑

As explained in other sections, certain exit status values have been reserved for special uses and should be used by applications only for those purposes:

• 126 — A file to be executed was found, but it was not an executable utility.
• 127 — A utility to be executed was not found.
• >128 — A command was interrupted by a signal.

memorize these, iykyk. they're the classic trio. 🔥

The behavior of exit when given an invalid argument or unknown option is unspecified, because of differing practices in the various historical implementations. A value larger than 255 might be truncated by the shell, and be unavailable even to a parent process that uses waitid() to get the full exit value. It is recommended that implementations that detect any usage error should cause a non-zero exit status (or, if the shell is interactive and the error does not cause the shell to abort, store a non-zero value in "$?"), but even this was not done historically in all shells.

ngl the historical shells were kind of a mess about this. we said what we said. 💅

🌈 FUTURE DIRECTIONS 🌈

None.

🔥 SEE ALSO 🔥

• Section 2.14, Special Built-In Utilities

📜 COPYRIGHT 📜

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

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and that's the whole page, bestie 🎀 this little queen shipped under IEEE/The Open Group, 2017, and yes — the footer says EXIT(1POSIX) too, because she's the main character in every single line. bye love u 💖✨