Write out all variables and their values:
set
Set $1, $2, and $3 and set "$#" to 3:
set c a b
Turn on the -x and -v options:
set -xv
Unset all positional parameters:
set --
Set $1 to the value of x, even if it begins with '-' or '+':
set -- "$x"
Set the positional parameters to the expansion of x, even if x
expands with a leading '-' or '+':
set -- $x
