SHIFT(1POSIX)

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.

NAME
shift — shift positional parameters

SYNOPSIS

shift [n]

DESCRIPTION
The positional parameters shall be shifted. Positional parameter 1 shall be assigned the value of parameter (1+n), parameter 2 shall be assigned the value of parameter (2+n), and so on. The parameters represented by the numbers "$#" down to "$#-n+1" shall be unset, and the parameter '#' is updated to reflect the new number of positional parameters.

The value n shall be an unsigned decimal integer less than or equal to the value of the special parameter '#'. If n is not given, it shall be assumed to be 1. If n is 0, the positional and special parameters are not changed.

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
If the n operand is invalid or is greater than "$#", this may be considered a syntax error and a non-interactive shell may exit; if the shell does not exit in this case, a non-zero exit status shall be returned. Otherwise, zero shall be returned.

CONSEQUENCES OF ERRORS
Default.

The following sections are informative.

APPLICATION USAGE
None.

EXAMPLES

$ set a b c d e
$ shift 2
$ echo $*
c d e

RATIONALE
None.

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 .