You should post the first lines of your program as:

#!/usr/bin/perl
use strict;
use warnings;
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as they provide help to find errors in your code.

Maybe chomp: chomp(my @modules = `lsmod`); will eliminate the extra newlines.

The module Perl6::Form may be of help here although I've not used it, and there's a bit of documentation and I haven't read it all.

I tried something like this

#!/usr/bin/perl
use strict;
use warnings;
use Perl6::Form;

my @modules = <DATA>;

for (@modules) {
    my ($tables, $count, $count2, $text) = split;
    print form "{<<<<<<<<<<} {>>>>>}  {>>} {[[[[[[[[[[[[[[[[[[[[[[[[[[
+[[[[[[}",
                $tables,     $count, $count2, $text;
}

__DATA__
ip_tables               9688  3 iptable_mangle,iptable_nat,iptable_fil
+ter
x_tables                8964  17 xt_CONNMARK,xt_length,xt_tcpudp,ipt_d
+scp,ipt_ipp2p,xt_connmark,ipt_multiport,xt_state,ipt_TOS,xt_CLASSIFY,
+ipt_ACCOUNT,ipt_MASQUERADE,ipt_REDIRECT,ipt_REJECT,ipt_LOG,iptable_na
+t,ip_tables
sch_htb                14464  0
sch_sfq                 4992  0
ppp_async               8192  0
crc_ccitt               2048  1 ppp_async
ppp_synctty             6912  0
ppp_generic            21140  2 ppp_async,ppp_synctty
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Output is

C:\perlp>perl t2.pl
ip_tables       9688     3 iptable_mangle,iptable_nat,iptabl-
                           e_filter
x_tables        8964    17 xt_CONNMARK,xt_length,xt_tcpudp,i-
                           pt_dscp,ipt_ipp2p,xt_connmark,ipt-
                           _multiport,xt_state,ipt_TOS,xt_CL-
                           ASSIFY,ipt_ACCOUNT,ipt_MASQUERADE-
                           ,ipt_REDIRECT,ipt_REJECT,ipt_LOG,-
                           iptable_nat,ip_tables
sch_htb        14464     0
sch_sfq         4992     0
ppp_async       8192     0
crc_ccitt       2048     1 ppp_async
ppp_synctty     6912     0
ppp_generic    21140     2 ppp_async,ppp_synctty
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