45.15 How to Unset all Command-Line Parameters

The shift (44.17 ) command "shifts away" one command-line parameter. You can shift three times if there are three command-line parameters. Many shells also can take an argument, like shift 3 , that tells how many times to shift; on those shells, you can shift  $# (44.15 ) to unset all parameters.

The portable way to unset all command-line parameters is probably to set (44.19 ) a single dummy parameter, then shift it away:

set x
shift

Setting the single parameter wipes out whatever other parameters were set before.