in reply to ip sorting

Ok, but I'd like to see what your try was (untested code follows). 

#!/usr/bin/perl
use warnings;
use strict;
use Socket qw( inet_aton inet_ntoa);

# takes file paths as argument
for (@ARGV) {
    local $, = $/;
    open my $fh, '<', $_ or die $!;
    print map  { inet_ntoa($_) }
          sort { $a <=> $b }
          map  { chomp; inet_aton($_) }
          <$fh>;
    print $/;
    close $fh or die $!;
}

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That will need perl 5.6+ to handle lexical filehandles and 3-arg open. Minor adjustment to run on older versions.

Update: pg++, thanks for catching my error. I'll leave this as it is, see pg's reply below.

After Compline,
Zaxo

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Re: Re: ip sorting
by pg (Canon) on Mar 21, 2003 at 04:35 UTC
    This solution is actually on the right track.

    The only mistake is that the author thought the result from inet_aton is a number, but it is not. In fact, the result returned is a string.

    Simply modify that sort statement to: 
    sort {$a cmp $b}

    [download]
    Now this piece of code works properly (I tested the modified version).

    If you are interested in details, inet_aton converts ascii address into a c structure in_addr, i.e. 
    struct in_addr {
    union {
        struct { u_char s_b1,s_b2,s_b3,s_b4; } S_un_b;
        struct { u_short s_w1,s_w2; } S_un_w;
        u_long S_addr;
    } S_un;
}

    [download]
    ,which Perl interprets as a string, not an unsigned long.

    My testing code: 
    use strict;
use Socket qw( inet_aton inet_ntoa);

local $, = $/;
print map  { inet_ntoa($_) }
      sort { $a cmp $b }
      map  { chomp; inet_aton($_) }
      <DATA>;
    print $/;
__DATA__
128.1.1.0
127
23.4.5.6
255.255.255.255
45.27.128.0
localhost

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[reply]
[d/l]
[select]
      I had asked the original question regarding ip sorting. I
      had to come back in here because I'd said that the man -g
      worked fine. However, the list I'd tested it on wasn't
      long enough for a real test. It does not work.

      However pg's slight modification to Zaxo's original code
      did the trick. Thanks very much.

      My apologies for duplicating a thread. I've not been here before.

      Thanks everyone!

[reply]
Re: Re: ip sorting
by Anonymous Monk on Mar 20, 2003 at 23:57 UTC
    I'm not a perl programmer, and my example would cause laughter for everyone else and embarrassment for me. :)

    Here's the output from the untested code:

    Argument "BmM-oM-5" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "CM-c\ng" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-Q\nM-Ri" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-QC^CM-B" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "BM-o^CI" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-QC\0M-2" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-Q\nM-Ri" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-QC^CM-L" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-OM-^\M-X$" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "D>Ge" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "E^AM-BJ" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    Argument "M-X^OM-\fM-^E" isn't numeric in sort at /usr/bin/ipsort line 13, <$fh> line 12.
    66.109.239.181
    67.227.10.103
    209.10.210.105
    209.67.3.194
    66.239.3.73
    209.67.0.178
    209.10.210.105
    209.67.3.204
    207.156.216.36
    68.62.71.101
    69.1.194.74
    216.15.140.133

    Thanks for everyone's time.

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