shift man page

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.

shift ā€” 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

Info

2013 IEEE/The Open Group POSIX Programmer's Manual