>perl -wMstrict -le
"my $line =
   'xxx:agent_id=>foo,yyy:agent_id=>b\"a\"r,zzz:agent_id=>\"baz\",qqq';
 print qq{'$line'};
 ;;
 my @agents;
 while ($line =~ m{ :agent_id=> (.+?) , }xmsg) {
   my $agent_id = $1;
   printf qq{extracted agent id: '$agent_id'  };
   $agent_id =~ s/\"//g;
   print qq{fixed agent id: '$agent_id'};
   push @agents, $agent_id;
   }
 printf qq{'$_' } for @agents;
"
'xxx:agent_id=>foo,yyy:agent_id=>b"a"r,zzz:agent_id=>"baz",qqq'
extracted agent id: 'foo'  fixed agent id: 'foo'
extracted agent id: 'b"a"r'  fixed agent id: 'bar'
extracted agent id: '"baz"'  fixed agent id: 'baz'
'foo' 'bar' 'baz'