shift(1) — Reliant UNIX 5.44c4

shift(1)                                                           shift(1)

NAME
     shift - shift values of positional parameters to the left

SYNOPSIS
     shift[ n]

DESCRIPTION
     The shell built-in shift shifts the values of positional parameters
     over to the left. shift without arguments thus results in the follow-
     ing:

     -  Shell parameter $0 (the command name) is unaffected.

     -  The original value of $1 is lost; this value can no longer be
        accessed.

     -  Instead, $1 takes the original value of $2, $2 that of $3, and so
        on until $8, which takes the value of $9.

     -  The tenth command-line argument is passed to the last positional
        parameter $9.

     -  $# is reduced by one.

     -  $* and $@ contain all command-line arguments, starting with the new
        value of $1. The original value of $1 is dropped.

     By default, the shell provides positional parameters which give you
     direct access to only the first nine command-line arguments of a set
     command or a shell script. This restriction can be bypassed with
     shift, since it allows you to move values over to the left by the
     required number of places.

OPERANDS
     n    A positive integer; shift is executed n times. This means that
          positional parameter $1 takes the value of the (n+1)th command
          line argument, etc.

          If the value of n is too large, shift issues an error message as
          soon as no command-line argument is available for $1; i.e. $# is
          equal to 0.

          n not specified:

          shift is executed once.

          If $1 already contains the last argument, the next invocation of
          shift will result in an error message.







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shift(1)                                                           shift(1)

ERROR MESSAGES

     script: cannot shift

     This error message is issued when $# is equal to 0, i.e. when no value
     could be passed to $1.

LOCALE
     The LCMESSAGES environment variable governs the language in which
     message texts are displayed. If LCMESSAGES is undefined or is defined
     as the null string, it defaults to the value of LANG. If LANG is like-
     wise undefined or null, the system acts as if it were not internation-
     alized.

     The LCALL environment variable governs the entire locale. LCALL
     takes precedence over all the other environment variables which affect
     internationalization.

EXAMPLES
     Example 1

     The tenth command-line argument is to be accessed in a shell script:

     .
     .
     arg1=$1
     shift
     arg10=$9
     .
     .
     .

     The original value of $1 is assigned to the arg1 variable. The value
     thus remains accessible even after the shift command.

     Example 2

     The following interactive session demonstrates the changes that take
     place in the values of the shell parameters $1, $*, and $# when shift
     is invoked:

     $ set 1 2 3 4 5 6 7 8 9 10 11 12
     $ echo $1
     1
     $ echo $#
     12
     $ echo $*
     1 2 3 4 5 6 7 8 9 10 11 12
     $ shift 6
     $ echo $1
     7



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shift(1)                                                           shift(1)

     $ echo $*
     7 8 9 10 11 12
     $ echo $#
     6

NOTES
     Some differences in behavior may occur when using shift, depending on
     which shell is being used. The possible differences are not described
     specifically.

SEE ALSO
     ksh(1), set(1), sh(1).










































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