Formatting text, eg long lines

nanouk has asked for the wisdom of the Perl Monks concerning the following question:

Hi all, I'm trying to format the output of lsmod for inclusion in a phpBB forum so that the lines get wrapped nicely at a certain length and you don't have to scroll horizontally forever to hit the reply button. And I'd like to do the same with the apache error log. Starting with the output of lsmod I tried different approaches garnered on the net none of which produced the expected result. Something I tried:

#!/usr/bin/perl
use Text::Wrap;
$Text::Wrap::columns = 100;
@modules = `lsmod`;
print Text::Wrap::fill( '', '', @modules );
[download]

It produces this output:

ip_tables 9688 3 iptable_mangle,iptable_nat,iptable_filter

x_tables 8964 17
xt_CONNMARK,xt_length,xt_tcpudp,ipt_dscp,ipt_ipp2p,xt_connmark,ipt_mul
+tiport,xt_state,ipt_TOS,xt_CL
ASSIFY,ipt_ACCOUNT,ipt_MASQUERADE,ipt_REDIRECT,ipt_REJECT,ipt_LOG,ipta
+ble_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
[download]

It's the closest I've come to my goal but you see there are extraneous carriage returns as compared to the lsmod output:

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]

And also you lose the original formatting by neat columns. Is there a solution to my problem ?
TIA
Cheers, Pascal

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Re: Formatting text, eg long lines by wind (Priest) on Nov 30, 2007 at 10:08 UTC
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 $data; __DATA__ ip_tables 9688 3 iptable_mangle,iptable_nat,iptable_fil +ter x_tables 8964 17 xt_CONNMARK,xt_length,xt_tcpudp,ipt_d +scp,ipt_ipp2p,xt_connmark,ipt_multiport,xt_state,ipt_TOS,xt_CLASSIFY, +ipt_ACCOUNT,ipt_MASQUERADE,ipt_REDIRECT,ipt_REJECT,ipt_LOG,iptable_na +t,ip_tables sch_htb 14464 0 sch_sfq 4992 0 ppp_async 8192 0 crc_ccitt 2048 1 ppp_async ppp_synctty 6912 0 ppp_generic 21140 2 ppp_async,ppp_synctty [download] - Miller	[reply] [d/l]
Re^2: Formatting text, eg long lines by nanouk (Novice) on Dec 03, 2007 at 11:15 UTC
Works a treat! Thanks a bunch. Cheers Pascal P.S. : would you please comment your code so that I could learn something?	[reply]
Re: Formatting text, eg long lines by Cristoforo (Curate) on Nov 30, 2007 at 20:17 UTC
You should post the first lines of your program as: `#!/usr/bin/perl use strict; use warnings;` [download] as they provide help to find errors in your code. Maybe chomp: chomp(my @modules = `lsmod`); will eliminate the extra newlines. The module Perl6::Form may be of help here although I've not used it, and there's a bit of documentation and I haven't read it all. I tried something like this #!/usr/bin/perl use strict; use warnings; use Perl6::Form; my @modules = <DATA>; for (@modules) { my ($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 [download] 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` [download]	[reply] [d/l] [select]