No it doesn't. I understand that you are learning and am really not trying to beat you up here but before saying something works you should verify the output against the expected results. I have only slightly modified your code, but I left in your case sensitivity mistake SEP vs sep.

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

my @array;
while( <DATA> ) {
  @array = (@array,$_);
  if (/<sep>/) {
    print join '',sort {$a <=> $b} @array;
    print "<sep>\n";
    @array=();
  }
}
print join '',sort {$a <=> $b} @array;
__DATA__
<sep>
22
1
3
<sep>
4
2
44
[download]

Argument "<sep>\n" isn't numeric in sort at foo.pl line 14, <DATA> lin
+e 8.
Argument "<sep>\n" isn't numeric in sort at foo.pl line 14, <DATA> lin
+e 8.
<sep>
<sep>
1
2
3
4
22
44
[download]

with sort.in

<SEP>
4
99
63
2
1
<SEP>
8
1
12
<SEP>
3
2
1
[download]

my code produces this now

<SEP>
1
2
4
63
99
<SEP>
1
8
12
<SEP>
1
2
3
[download]

before it also seemed to be sorting it correctly but when I turned on warnings and strict I saw the errors you where talking about:

Argument "\x{3c}\x{53}..." isn't numeric in sort at foo.pl line 8, <IN
+> line 7.
Argument "\x{3c}\x{53}..." isn't numeric in sort at foo.pl line 8, <IN
+> line 11.
Argument "\x{3c}\x{53}..." isn't numeric in sort at foo.pl line 14, <I
+N> line 14.
[download]

I appreciate the helpful critisim, thank you.


daN.