The shift Statement
You use the shift
statement to process the positional parameters, one at a time, from left to right. Recall that the positional parameters are identified as $1
, $2
, $3
, and so on. The effect of the shift
command is that each positional parameter is moved one position to the left and the current $1
parameter is lost.
The shift
statement is useful when you are writing shell programs in which a user can pass various options. Depending on the specified option, the parameters that follow can mean different things or might not be there at all.
The format of the shift
command is as follows:
shift number
The parameter number
is the number of places to be shifted and is optional. If not specified, the default is 1
; that is, the parameters ...
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