linux - Is this an effective way to wait 10 seconds for an IP address? -

i have shell script creates vm use processing on. vm given random ip address obtain using vmwares vmrun utility. machine can take anywhere 10 - 20 seconds before gets assigned ip address not default windows apipa address.

sometimes arithmetic error, , other times don't... whats wrong code? why intermittently work?

ip=`vmrun -t ws readvariable my_vm guestvar ip` if [ ! -z `echo $ip | grep "169.254"` ]   i=0   while [ ! -z `echo $ip | grep "169.254"` ]       if [ $i -eq 10 ]           echo "$ip has been unresponsive 10 seconds.  quitting."       exit 1     else       sleep 1       i=$((i++))  # error occurs       ip=`vmrun -t ws readvariable my_vm guestvar ip`     fi   done fi 

is there better way this?

error message:

arithmetic expression: expecting primary: "i++" 

the $ looks it's superfluous, can use ((i++)) without assignment increment variable.