Question

I am having problem in parsing the output from the text file. I want to add pipe symbol in between the character to do mutliple search similar to egrep, the text file is as follows

service entered the stopped state,critical
service entered the running state,clear

Code:

open(my $data, '<', $Config_File) or die "Could not open '$Config_File"
my $reg_exp;
my $severity;
my @fields=();
while (my $line = <$data>) 
{  
   chomp $line;   
   if(!$line =~ /^$/)
   {
   @fields = split "," , $line;
   $reg_exp = $fields[0];
   $severity = $fields[1]; 
   print $reg_exp;
   }
 }

 #print $fields[0];
 #last unless defined $line;

 close($data);

expected output

service entered the stopped state|service entered the running state

Answer 1

You are not far off, you just need to actually concatenate the strings. The simplest way would be to push the $fields[0] to an array, and wait until the input is done to print it. I.e.:

my @data;
while (my $line = <$data>) {
   next if $line =~ /^$/;            # no need to chomp
   my @fields = split /,/, $line;
   push @data, $fields[0];
}
print join("|", @data), "\n";

I sense that you are trying to achieve something else with this code, and that this is a so-called XY-problem.