I don't think anyone has mentioned changing the record/line delimiter yet which seems like a good approach for this problem especially if you have multiple records in a file. You asked about processing line by line. That's the default because the delimiter ($/) is a newline (\n) by default (usually, different systems and read modes affect this too). You could play around with this.

{
    local $/ = "<SUBEND"; # localize or this is a bad idea.
    my $count = 0;
    while (<YOUR_FILE_HANDLE>)
    {
        next unless /SUBBEGIN/; # Don't catch trailing empty stuff.
        print "\nRECORD ", ++$count, " -------------------------\n";
        print $_;
    }
}
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tybalt89 suggested changing the delimiter in the previous thread, FWIW.

Of course. Thanks. I was surprised it (apparently) hadn't come up.

Process record by record rather than line by line (as suggested by Your Mother) then top-and-tail and use split to break into line items then key/value pairs, populating a HoA structure. Then use grep to see if both items of interest are present. I added a record with one item missing to test.

The output.

Record No. 1 - Both present
Record No. 2 - One or both missing
[download]

I hope this is helpful.

Update: Corrected shonky wording ... and later deleted spurious square bracket.

#!/usr/bin/perl                                                    
use strict;
use warnings;
use feature 'say';                                                 
    
my $HSSIN = shift or die "usage: $0 <inputfile";                   
open my $infile, $HSSIN or die "Can't open input file";            
    
my ($MSISDN, $cfu_found, $cfb_found);                              
    
while (<$infile>) {

    # this is true for all lines between these two markers 
    if (/^\s*<SUBBEGIN/.. /^<SUBEND/)  {                          

        if (/MSISDN=(.+)/){                                        
            $MSISDN = $1;                                          
        }
        if (/^\s*CF=CFU-TS10-ACT/){                                
            $cfu_found = 1;
        }
        if (/^\s*CF=CFB-TS10-ACT/){
            $cfb_found = 1;                                        
        }
    }
}   

if ($cfu_found and $cfb_found){
    say "cfu and cfb both found and MSISDN is $MSISDN";            
}
[download]

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

sub callForwardingsCF {
    my ($found) = @_;
    $found->{1} = 1 if /\t*CF=(CFU-TS10-ACT-(NONE|\d+))/;
    $found->{2} = 1 if /\t*CF=(CFB-TS10-ACT-(NONE|\d+))/
}

my %found;
while (<>) {
    if (/<SUBEND/)  {
        say "SUBEND found";
        if (2 == keys %found) {
            print "Both expressions found.\n";
        } elsif (keys %found) {
            print "Found only expression ", keys %found, ".\n";
        } else {
            print "None of the expressions found.\n";
        }
        %found = ();
    }
    callForwardingsCF(\%found);
}
[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]

Hello gbwien,

I was under the impression that your question was answered before Grouped Regular Expression not set assign default value. In case that was not answered from your sample of code you are creating a function and you call the function internally of the function again without processing any parameters.

I am not sure what you want. Do you want to pass the file e.g. inside the function and retrieve the output?

Can you provide us with more information?

Looking forward to your reply, BR.

Hi thanos1983, Thanks for your help. Yes part of my questions were answered in that post but I still have other questions relating to resolving the entire problem. In the example program I provided I am trying to trigger the scenario were two lines are found to exist in an input file, in this case the lines CFU-TS10-ACT and CFB-TS10-ACT. If I change the if statement to the following then this works fine as would be expected

if (/\t*CF=(CFU-TS10-ACT-(NONE|\d+))/)
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But I do not know how to check for the existence of two lines.

Hello again gbwien,

Try something like this:

Read more... (3 kB)

Since you did not provide us with more than one subsection of your file or desired output I am not able to help you more than that.

Hope this helps, BR.

Seeking for Perl wisdom...on the process of learning...not there...yet!

See How do I read an entire file into a string?. You might also consider applying consistent indentation to your code.

#!/usr/bin/perl 
use strict;
use warnings;

my $HSSIN='D:\testproject\HSS-export-test-run-small.txt';
my $ofile = 'D:\testproject\HSS-output.txt';
open (INFILE, $HSSIN) or die "Can't open input file";
open (OUTFILE,"> $ofile" ) or die "Cant open file"; 


my $content = undef;
{undef $/; $content = <INFILE> } close(INFILE);

my $num_found = 0;
while( $content =~ /\t*CF=(CFU-TS10-ACT-(NONE|\d+))/g ){ $num_found++ 
+}
print "multiple cases: $num_found cases of ... " if $num_found > 0;

...
[download]

You could read each record into an array, and check it as a unit:

#!/usr/bin/env perl
use strict;
use warnings;
use feature qw(say);
use List::Util qw(first);

my $rec_no = 0;
my @record;
my $msisdn;

while(<>){
    chomp;
    if(/^<SUBBEGIN/){
        @record = ($_);
        $msisdn = undef;
        say "Found record: ", ++$rec_no;
        next;
    }elsif(/^<SUBEND/){
        push @record, $_;
        check_record(\@record);
        @record = ();
    }elsif(/^\s*MSISDN=(\d+);/){
        $msisdn = $1;
        say "Record $rec_no: MSISDN = $msisdn";
    }else{
        push @record, $_;
    }
}

exit 0;


sub check_record {
    my $listref = shift;
    if(     first {/^\s*CF=(CFU-TS10-ACT-(NONE|\d+))/} @{$listref}
        and first {/^\s*CF=(CFB-TS10-ACT-(NONE|\d+))/} @{$listref}
    ){
        say "this case is found here .....";
    }
}
[download]

It's a bit of a brute-force solution, but it should work.

Sample output:

$ ./t.pl
Found record: 1
Record 1: MSISDN = 1234567890
this case is found here .....
Found record: 2
Record 2: MSISDN = 1234567890
this case is found here .....
[download]

Yes I am the author of that post, point taken I will provide that information in the future. Thank you. https://stackoverflow.com/questions/49490941/check-if-multiple-lines-exist-in-text-file

"<SUBBEGIN..."

I got a Déjà-vu, right? What file format is this? If i didn't ask yet...