#!/usr/bin/ksh
destination_server=servename
destination_user_id=un
destination_password=pw

myfile=/dir1/xxx.dat
while true
 do
  if [[ -a $myfile ]]; then
    echo "$myfile exists!"
    ftp -v -n $destination_server <<END
     user $destination_user_id $destination_password
     cd dir3
     put $myfile
    END
    
    echo 'FTP Complete'
  else
    sleep 600
  fi
done