setup-routing.sh

# this is a partial of a script that does my setup-routing. I needed to modify it to accept parameters. 
# performs round-robin like link assignment

# args processing
function echo_usage {
  echo "Usage: `basename $0` [link]* (defaults to last run params if exists, or ppp101 ppp102)"
}

if [ "$1" == "-h" ]
  echo_usage
  exit 1
fi
#get last run params
srparams=/etc/setup-routing.params
if [ -s $srparams ]
  link_array=(`cat $srparams`)
else
  link_array=(ppp101 ppp102)
fi
if [ $# -gt 0 ]
  link_array=($@)
fi 
#link_array=(ppp101 ppp102 dsl1 covad0 covad)
len=${#link_array[@]}
rt_table='/etc/iproute2/rt_tables'
link_array=(${link_array[@]/dsl/ppp10})
#check if valid input, else exit
count=0
while [ $count -lt $len ];do
  if ! grep -q "[ ]${link_array[$count]}$" $rt_table; then
    exit 1
    #unset link_array[$count]
    #echo "$tmplink is not a valid link"
    #len=$(( $len -1 ))
  fi
  count=$(( $count + 1 ))
done

#save last run params
echo ${link_array[$@]} > $srparams

...setup routing code

prefix=192.168.1
prio=200
for n in `seq 1 199` `seq 211 253`; do
  let id=(( ($n-1) % $len ))
  $ip rule add pref $((prio++)) from $prefix.$n table ${link_array[$id]}
done