LDP/LDP/guide/docbook/abs-guide/unset.sh

#!/bin/bash
# unset.sh: Unsetting a variable.

variable=hello                       #  Initialized.
echo "variable = $variable"

unset variable                       #  Unset.
                                     #  In this particular context,
                                     #+ same effect as:   variable=
echo "(unset) variable = $variable"  #  $variable is null.

if [ -z "$variable" ]                #  Try a string-length test.
then
  echo "\$variable has zero length."
fi

exit 0