Once you've opened the directory and gotten a list of files, you could use this snippet to proceed.

FILE_LIST: foreach my $filename ( @files ) {
    open FILE, "<", $filename or die "Can't open $filename. $!\n";
    my $headers = 0;
    while ( my $line = <FILE> ) {
        $headers++ if $line =~ /\bFULL\b/;
        if ( $headers > 1 ) {
            # do whatever it is you intend to do with
            # multi-header'ed files.
            next FILE_LIST;
        }
    }
    # Do whatever it is you intended to do with
    # single-header files.
} continue {
    close FILE;
}
# Now you're done.
[download]

As you can see, Regular Expressions! are only a very small part of making this thing work for you.

Unless I'm mistaken, this snippet should go a good ways toward solving your problem.

use File::Spec::Functions;
use File::Copy;

our @files = glob "*.txt";

mkdir for qw( multiple single );

for my $file ( @files ) {
    if ( 1 > number_of_headers( $file ) ) {
        move( $file, catfile( "multiple", $file ) );
    } else {
        move( $file, catfile( "single", $file ) );
    }
}

sub number_of_headers {
    my $file = shift;
    my $count = () = slurp( $file ) =~ /FULL/g;
    return $count;
}

sub slurp {
    my $file = shift;
    local $/;
    local *SLURP;
    open SLURP, "<", $file or die "Couldn't open $file for reading: $!
+";
    my $content = <SLURP>;
    close SLURP or warn "Couldn't close $file: $!";
    return $content;
}
[download]

I have used the code by l2kashe:

Looks like its moving everything from one directory to the other.

#!/usr/bin/perl

use strict;

my $data   = '/path/to/base/dir';
my $multi  = '/path/to/multi/full/dir';
my $single = '/path/to/single/full/dir';

opendir(DATA, $data) or die "Cant opendir $data: $!\n";

for ( grep !/^\./, readdir(DATA) ) {
   my $in = "$data/$_";

   open(IN, $in) or die "Cant open $in: $!\n";
   my $count = grep /^(?:\s+|)FULL/, <IN>;
   close(IN);

   if ( $count >= 2 ) {
      rename($in, "$multi/$_") 
         or (warn "Couldnt move $_ to $multi: $!\n" and next);
   
   } else {
      rename($in, "$single/$_")
         or (warn "Couldnt move $_ to $single: $!\n" and next);
   }
} # END for grep
closedir(DATA)
[download]

Edit, BazB: close code tag, remove random characters.

Im going to go out on a limb, and make an assumption that files are the only files in said directory, and that 'full' will only occur around the beginning of a line. With that said

#!/usr/bin/perl

use strict;

my $data   = '/path/to/base/dir';
my $multi  = '/path/to/multi/full/dir';
my $single = '/path/to/single/full/dir';

opendir(DATA, $data) or die "Cant opendir $data: $!\n";

for ( grep !/^\./, readdir(DATA) ) {
   my $in = "$data/$_";

   open(IN, $in) or die "Cant open $in: $!\n";
   my $count = grep /^(?:\s+|)FULL/, <IN>;
   close(IN);

   if ( $count >= 2 ) {
      rename($in, "$multi/$_") 
         or (warn "Couldnt move $_ to $multi: $!\n" and next);
   
   } else {
      rename($in, "$single/$_")
         or (warn "Couldnt move $_ to $single: $!\n" and next);
   }
} # END for grep
closedir(DATA);
[download]

Edit: added test for success on rename :P..

use perl;

I just need to copy files from the source into 2 different directories
+ one with single header and the other with multiple headers!


ANy help would be appreciated...thanks a lot!


Global symbol "$data" requires explicit package name at test3_final.pl
+ line 4.
Global symbol "$ONE" requires explicit package name at test3_final.pl 
+line 5.
Global symbol "$TWO" requires explicit package name at test3_final.pl 
+line 6.
Global symbol "$data" requires explicit package name at test3_final.pl
+ line 8.
Global symbol "$data" requires explicit package name at test3_final.pl
+ line 8.
Global symbol "$data" requires explicit package name at test3_final.pl
+ line 11.
Global symbol "$TWO" requires explicit package name at test3_final.pl 
+line 18.
Global symbol "$ONE" requires explicit package name at test3_final.pl 
+line 21.
Execution of test3_final.pl aborted due to compilation errors.


use strict;

$data = "/export/home/credpol03/e7uryp/PERL/test";
$ONE = "/export/home/credpol03/e7uryp/PERL/ONE";
$TWO = "/export/home/credpol03/e7uryp/PERL/TWO";


opendir(DATA, $data) or die "Cant opendir $data: $!\n";

for ( grep !/^\./, readdir(DATA) ) {
   my $in = "$data/$_";

   open(IN, $in) or die "Cant open $in: $!\n";
   my $count = grep /^(?:\s+|)FULL/, <IN>;
   close(IN);

   if ( $count >= 2 ) {
      rename($in, "$multi/$_");

   } else {
      rename($in, "$single/$_");
   }
} # END for grep
closedir(DATA);
[download]