use strict;

my $title;

while ( <DATA> )
{
    $title = $_ if /^Title: .+$/;
    print $title, $_ if /^856   invalid/;
}

close IN;

__DATA__
Title:  Mary moo-cow 
856   invalid url

Title:  the mechanics 
856  valid url

Title:  Terminator 2
856   invalid url
[download]

Hai just try this

$str='url Title: Mary moo-cow 856 invalid 
url Title: the mechanics 856 valid 
url Title: Mary moo-cow 858 invalid';

my @string =split/\n/, $str;

my @arr=();
for (@string)
{
if ($_ =~m#url Title:\s((.+?)\s(\d+)) invalid#gsi)
{
push(@arr,$1);
}
}

print "$_\n" for @arr;
[download]

output:

Mary moo-cow 856

Mary moo-cow 858

Hi, just try this with created file

open(IN, "d:\\temp.txt")    ||    die "Cannot open file";

while (<IN>) {    
    if ($_ =~ m#url Title: (.*?) invalid#gsi) {
    push(@arr, $1);
    }
}
$"="\n";
print "@arr";
[download]

Regards,
Gubendran

you could also try this

cat YourFile|perl -pe'$/="Title:";chomp;$_=/invalid url/?"Title:".$_:"
+"'
[download]

A quick explanation as this does look a bit line noise like. Perl is started with the options p and e. e gives the code to execute on the command line, p puts a while loop around the code with a continue block that just prints $_.

A very useful trick is to deparse a script to see better what is going on, lets do that now to make it more readable and so you can see the while and print added by the -p

pre> perl -MO=Deparse -pe'$/="Title:";chomp;$_=/invalid url/?"Title:".
+$_:""'
-e syntax OK
LINE: while (defined($_ = <ARGV>)) {
    $/ = 'Title:';
    chomp $_;
    $_ = /invalid url/ ? 'Title:' . $_ : ''
}
continue {
    print $_;
}
[download]

The chomp removes the record seperator (Title:) from the end of the record, trailing titles would be ugly.

The last part sets $_ depending on whether the block we are examining contains the string "invalid url". The Test?value1:value2 construct returns the first value if the test is true and the second if it fails. In this case we either fix up $_ for printing by prefixing "Title:" or we set it to an empty string so nothing is printed.

Cheers,
R.

if u wish just try this in your file

input "test.txt"

*******************************

Title: Mary moo-cow 856 invalid

Title: the mechanics 857 valid

Title: Mary moo-cow 858 invalid

Title: the mechanics 856 valid

Title: Mary moo-cow 859 invalid

Title: the mechanics 8500 valid

undef $/;
open(FIN,"d:\\temp.txt");
$str=<FIN>;
close($str);

while($str =~m#Title: (.*?) invalid#gi)
{
push(@arr,$1);
}
print "$_\n" for @arr;
[download]

output

***********

Mary moo-cow 856

Mary moo-cow 858

Mary moo-cow 859