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true(1p) [posix man page]

TRUE(1P)						     POSIX Programmer's Manual							  TRUE(1P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
true -- return true value SYNOPSIS
true DESCRIPTION
The true utility shall return with exit code zero. OPTIONS
None. OPERANDS
None. STDIN
Not used. INPUT FILES
None. ENVIRONMENT VARIABLES
None. ASYNCHRONOUS EVENTS
Default. STDOUT
Not used. STDERR
Not used. OUTPUT FILES
None. EXTENDED DESCRIPTION
None. EXIT STATUS
Zero. CONSEQUENCES OF ERRORS
None. The following sections are informative. APPLICATION USAGE
This utility is typically used in shell scripts, as shown in the EXAMPLES section. The special built-in utility : is sometimes more effi- cient than true. EXAMPLES
This command is executed forever: while true do command done RATIONALE
The true utility has been retained in this volume of POSIX.1-2008, even though the shell special built-in : provides similar functionality, because true is widely used in historical scripts and is less cryptic to novice script readers. FUTURE DIRECTIONS
None. SEE ALSO
Section 2.9, Shell Commands, false COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/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 2013 TRUE(1P)

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EXIT(1P)						     POSIX Programmer's Manual							  EXIT(1P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
exit -- cause the shell to exit SYNOPSIS
exit [n] DESCRIPTION
The exit utility shall cause the shell to exit with the exit status specified by the unsigned decimal integer n. 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. OPTIONS
None. 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. 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. CONSEQUENCES OF ERRORS
Default. The following sections are informative. APPLICATION USAGE
None. EXAMPLES
Exit with a true value: exit 0 Exit with a false value: exit 1 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. 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, 2013 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/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 2013 EXIT(1P)
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