SHIFT(1)                   POSIX Programmer's Manual                  SHIFT(1)



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

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 $*
       cc dd ee

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 .



IEEE/The Open Group                  2017                             SHIFT(1)
