Perl put lines in a file in to a single file

Question

I have a file called mail.txt in which lines are printed like below ,i want to put all those lines in to one single line like

Thanks

---

This is the input

q2VDWKkY010407  2221878 Sat Mar 31 19:37 <Mailer-daemon>
                     (host map: lookup (my.local.domain): deferred)
                                             <[email protected]>
                                             <[email protected]>
q2VDWKkY010407  2221878 Sat Mar 31 19:37 <Mailer-daemon>
                     (host map: lookup (my.local.domain): deferred)
                                             <[email protected]>
                                             <[email protected]>

This is the output

q2VDWKkY010407  2221878 Sat Mar 31 19:37 <Mailer-daemon>,(host map: lookup (my.local.domain): deferred),<[email protected]>,<[email protected]>

q2VDWKkY010407  2221878 Sat Mar 31 19:37 <Mailer-daemon>,(host map: lookup (my.local.domain): deferred), <[email protected]>,<[email protected]>

Answer 1

So why don't you just do it?

open(my $fh, "<", $input_filename);

my @lines = map { chomp; $_} <$fh>; #1

close $fh;

open(my $out, ">", $output_filename);

print $out join "", @lines; # or maybe a different separator, like ","

close $out;

#that's it

Note: if you want to get rid of the extra spaces at the beginnings and ends of input lines, you can replace line #1 by

my @lines = map { s/\s+$//; s/^\s+//; $_} <$fh>;