Because you have the line use strict, you will get the error "Global symbol "@fields" requires explicit package name at get_maid_num.pl line 10." if @fields is not defined.

You can define the array like so:
1. my @fields;
2. my @fields=();
Either 1 or 2 will work.


Now, if I am right here, look at the code below and see if this works for you:

#!/usr/bin/perl
use strict;

my $result;
my $komp_dir = "/Users/mydirectory/Desktop/BioinfDev/SequenceAssemblyP
+roject/KOMP/";

opendir(DIR, "$komp_dir");
my @FILES= readdir(DIR);
close DIR;

foreach my $file (@FILES) {
     if (-d "$komp_dir/$file") {
          $result = $file;
          print "$result\n";
     }  
}
[download]

OR

#!/usr/bin/perl
use strict;

my $result;
my $komp_dir = "/Users/mydirectory/Desktop/BioinfDev/SequenceAssemblyP
+roject/KOMP/";

opendir(DIR, "$komp_dir");
my @FILES= readdir(DIR);
close DIR;

foreach my $file (@FILES) {
     if (-d "$komp_dir/$file" && $file =~ /\d+_\w+/) {
          $result = $file;
          print "$result\n";
     }
}
[download]

Now you said you only wanted to capture number part, then do this:

#!/usr/bin/perl
use strict;

my $result;
my $komp_dir = "/Users/mydirectory/Desktop/BioinfDev/SequenceAssemblyP
+roject/KOMP/";

opendir(DIR, "$komp_dir");
my @FILES= readdir(DIR);
close DIR;

foreach my $file (@FILES) {
     if (-d "$komp_dir/$file" && $file =~ /(\d+)_\w+/) {
          $result = $1;
          print "$result\n";
     }
}
[download]