shift — Shift positional parameters

Format

shift [expression]

tcsh shell: shift [variable]

Description

shift renames the positional parameters so that i+nth positional parameter becomes the ith positional parameter, where n is the value of the given arithmetic expression. If you omit expression, the default value is 1. The value of expression must be between zero and the number of positional parameters ($#), inclusive. The value of $# is updated.

shift is a special built-in shell command.

In the tcsh shell, without arguments, shift discards argv[1] and shifts the members of argv to the left. It is an error for argv not to be set or to have less than one word as value. With variable, shift performs the same function on variable. See tcsh — Invoke a C shell.

Examples

The commands:

set a b c d
shift 2
echo $*

produce:

c d

Localization

shift uses the following localization environment variables:

LANG
LC_ALL
LC_MESSAGES
NLSPATH

See Localization for more information.

Exit values

0: Successful completion
1: Failure because the expression had a negative value or was greater than the number of positional parameters.

Messages

Possible error messages include:

bad shift count expr: You specified an expression that did not evaluate to a number in the range from 0 to the number of remaining positional parameters.

Portability

POSIX.2, X/Open Portability Guide, UNIX systems.

Allowing an expression, rather than just a number, is an extension found in the z/OS® UNIX shell.

Related information

set, sh, tcsh