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

use IO::All;
use Data::Dumper;

my @files = io('fileName.txt')->chomp->slurp;
print Dumper \@files;

__END__
$ perl test.pl
$VAR1 = [
          'a.txt',
          'b.txt',
          'c.txt'
        ];

##</code><code>##

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

use IO::All;
use Data::Dumper;

sub grepFileFromSubroutine {
    my @files = io(shift)->chomp->slurp;
    my @final;
    foreach my $file (@files) {
	if ( -e $file ) {  # double check existence
	    my @lines = io($file)->chomp->slurp; # Chomp as you slurp
	    if (my @matches = grep( /string/, @lines ) ) {
		push @final, "Found in File: '$file':", @matches;
	    }
	}
    }
    return \@final;
}

print Dumper grepFileFromSubroutine(@ARGV);

__END__

$ perl test.pl fileName.txt
$VAR1 = [
          'Found in File: \'a.txt\':',
          'Line two interested, string',
          'Found in File: \'b.txt\':',
          'Line one interested, string',
          'Line two interested, string'
        ];

__DATA__

$ cat a.txt b.txt c.txt
Line one not interested
Line two interested, string
Line one interested, string
Line two interested, string
Line one not interested
Line two not interested
Line three not interested