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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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EXIT(1P) POSIX Programmer's Manual EXIT(1P)
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.
exit — cause the shell to exit
exit [n]
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.
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.
None.
See the DESCRIPTION.
Not used.
None.
None.
Default.
Not used.
The standard error shall be used only for diagnostic messages.
None.
None.
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.
Default.
The following sections are informative.
None.
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"
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.
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.
None.
Section 2.14, Special Built-In Utilities
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 .
IEEE/The Open Group 2017 EXIT(1P)
Pages that refer to this page: return(1p), sh(1p)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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