行之间的perl行匹配

Question

I have a file.

Sun Sep  9 12:34:42 2012 : Sun Sep  9 12:34:42 2012 : [Req] Send Bcast 
Sun Sep  9 12:34:32 2012 : RX FROM :152.14.189.4 MESG: 
Sun Sep  9 12:34:32 2012 : info  
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.4 
Sun Sep  9 12:34:32 2012 : RX FROM :13 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.13  
Sun Sep  9 12:34:32 2012 : RX FROM :9 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.9  
Sun Sep  9 12:34:32 2012 : RX FROM :14 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.14 
Sun Sep  9 12:34:32 2012 : RX FROM :5 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.5 
Sun Sep  9 12:34:35 2012 : Reply back to 9 
Sun Sep  9 12:34:35 2012 : Reply back to 13
Sun Sep  9 12:34:36 2012 : Reply back to 14
Sun Sep  9 12:34:37 2012 : Reply back to 1.1.1.4 
Sun Sep  9 12:34:37 2012 : Reply back to 5 
Sun Sep  9 12:34:42 2012 : Sun Sep  9 12:34:42 2012 : [Req] Send Bcast 
Sun Sep  9 12:34:32 2012 : RX FROM :152.14.189.4 MESG: 
Sun Sep  9 12:34:32 2012 : info  
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.5 
Sun Sep  9 12:34:32 2012 : RX FROM :13 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.9  
Sun Sep  9 12:34:32 2012 : RX FROM :9 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.4  
Sun Sep  9 12:34:32 2012 : RX FROM :14 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.13 
Sun Sep  9 12:34:32 2012 : RX FROM :5 
Sun Sep  9 12:34:32 2012 : #ip=1.1.1.14 
Sun Sep  9 12:34:35 2012 : Reply back to 9 
Sun Sep  9 12:34:35 2012 : Reply back to 14
Sun Sep  9 12:34:36 2012 : Reply back to 13
Sun Sep  9 12:34:37 2012 : Reply back to 4 
Sun Sep  9 12:34:37 2012 : Reply back to 5 

Between Two lines "Bcast" I need to search for a value say 1.1.1.4 and if it is present at both ip=1.1.1.1 and Reply back to 1.1.1.4. Then I need to ignore that set. Else I need to write the differences in two separate files. I tried doing that in perl. When I to search between Bcast and Bcast, nothing is getting printed. Am i missing anything? Here is what i have written

open my $in,'<',$ARGV[0];
open my $out,'>',"File2.txt";
my $Flag =0;
while(<$in>){
        if (/Bcast/ .. /Bcast/)
        {
          print ;
          if ( ($_ =~ m{ ip=1\.1\.1\.4 }xms) )
          {
                  $Flag=$Flag+1;
                  print " \nMatch is Found !!! Hurray \n" if ($Flag==2);
          }       
        } 
      $Flag=0;
}   

Kindly help me

Answer 1

/Bcast/ .. /Bcast/ will start and stop on the same line. /Bcast/ ... /Bcast/ is a bit more promising, but then you realise you are skipping every second block.

In reality, you are always in a Bcast block once you find the first one, so you shouldn't be trying to find out if you're in one using a flip-flop.

# 0: Haven't see Bcast
# 1: Haven't seen "#ip=1.1.1.4" in this Bcast.
# 2: Haven't seen "Reply to 1.1.1.4" in this Bcast.
# 3: Found match
my $state = 0;  
while (<>) {   
    if (/Bcast/) {
       $state = 1;
    }

    if ($state == 1) {
       if (/ : \#ip=(\S+)/ && $1 eq '1.1.1.4') {
          $state = 2;
       }
    }
    elsif ($state == 2) {
       if (/ : Reply back to (\S+)/ && $1 eq '1.1.1.4') {
          $state = 3;
          print("Found match\n");
       }
    }
}

Note the your original code could accidentally match 1.1.1.43 .