sipgrep was created by Alexandr Dubovikov <shurik@start4.info>

It is a wrapper on ngrep which
 * filters SIP messages according number in To or From header fields
 * displays From tag, To tag, Call-ID and branch in
   different colours, thus it is possible to trace dialogs or transactions 
   by "one look into message" ... this is really great! ;-)
 * It can store received messages into a file and show them (together)

Known "issues":
 * you might need to change "path to ngrep", for example I changed it to
      $ngrep="sudo ngrep -d any";
   which runs ngrep on all interfaces under sudo for me

[ README written by Vaclav ]