The following works. Change $= and the "Mem Segments" part of the format to suit.

#!/usr/bin/perl -w

$= = 10;

my @x = (1..10);


format STDOUT_TOP =
+                      queue     proc_status
+                        |           |
+proc        prio        |    msg    |     log       broadcast   Share
+d Mem
+name                    |    type   |                  node      Segm
+ents
.

format STDOUT =
@|||||||      @||      @||||  @|||  @|| @||||||||||  @||||||||   @< @<
+ @< 
@x
.

for (1..12) {
    write;
    @x = map {$_ +1} @x;
}

__END__
Prints:

+                      queue     proc_status
+                        |           |
+proc        prio        |    msg    |     log       broadcast   Share
+d Mem
+name                    |    type   |                  node      Segm
+ents
   1           2         3     4     5       6           7       8  9 
+ 10
   2           3         4     5     6       7           8       9  10
+ 11
   3           4         5     6     7       8           9       10 11
+ 12
   4           5         6     7     8       9          10       11 12
+ 13
   5           6         7     8     9      10          11       12 13
+ 14
   6           7         8     9    10      11          12       13 14
+ 15
^L
+                      queue     proc_status
+                        |           |
+proc        prio        |    msg    |     log       broadcast   Share
+d Mem
+name                    |    type   |                  node      Segm
+ents
   7           8         9     10   11      12          13       14 15
+ 16
   8           9        10     11   12      13          14       15 16
+ 17
   9          10        11     12   13      14          15       16 17
+ 18
   10         11        12     13   14      15          16       17 18
+ 19
   11         12        13     14   15      16          17       18 19
+ 20
   12         13        14     15   16      17          18       19 20
+ 21
[download]

--
John.

The bare @'s in the format aren't syntactically correct.

Can you elaborate on that? They seem to work just fine, and how else would one get a single-character field anyway? The relevant doc is not specific on this, but I see that the Notes section has an example of a lone @ as a field. Your example works fine with the extra < removed, giving the expected output of the single most significant digit.

For that matter mhearse's example worked just fine for me also, once I removed the excess @ fields, so I suspect something else is going on in his case.

--
I'd like to be able to assign to an luser

You are correct. They are valid.

When I ran mhearse's example code I got the following error:

  Array found where operator expected at format.pl line 17, at end of 
+line
  (Missing operator before ?)
  syntax error at format.pl line 17, near "@ @ @ @ "
[download]

I misinterpreted this to mean that the bare @'s were the problem. However, as you point out, they are in fact valid and the error comes from the line wrapping around.

In which case, I can't say what is the problem. Setting $= to 600 or any other value works fine for me with perls from 5.00405 onwards.

--
John.