It looks like you could use a simple regular expression. Try the following:

use strict;

my $data = do {local $/; <DATA>};

# Will wrap lines longer then 50 characters
$data =~ s{(.{50})(?=.)}{$1\n}g;

print $data;

__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
[download]

- Miller