Shell Programming and Scripting

{
    unset A B C
    A=192.168.16.1
    B=192.168.32.1
    C=192.168.64.1

    # Add "var=" so that the code has something to work with following nawk's work
    for i in A=$A B=$B C=$C
    do
        # Use eval to make assignemnt
        # ...this will translate into var=nawk's output
        eval ${i%%=*}=$(echo "${i##*=}" | nawk -F. '{
            if ($3 >= 16 && $3 < 32)
                print "192.168.202.1"
            else
                print
        }')
    done
    echo A=$A
    echo B=$B
    echo C=$C
}

A=192.168.202.1
B=192.168.32.1
C=192.168.64.1

{
    unset A B C
    A=192.168.16.1
    B=192.168.32.1
    C=192.168.64.1

    for i in A=$A B=$B C=$C
    do
       echo $i | IFS="=..." read Var f1 f2 f3 f4
       if   [ $f3 -gt 16 -a  $f3 -lt 32 ] ; then
          eval $Var=192.168.202.1
       elif [ $f3 -gt 16 -a $f3 -lt 64 ]  ; then
          eval $Var=192.168.203.1
       fi
    done
    echo A=$A
    echo B=$B
    echo C=$C
}