#!/usr/bin/perl

use strict;

# make sure we can open input and output files
open( H, "host_list_file" ) or die "host_list_file: $!";
open( O, ">output.csv" ) or die "output.csv: $!";

# read host list
my @hosts = <H>;
close H;

chomp @hosts;  # remove "\r\n" from ends of lines

my @iplist;
for my $host ( @hosts ) {
    my $ip = ...
    # do whatever you do to get $ip for $host (and chomp if needed)
    push @iplist, $ip;
}


my %ipdata;
my @infolist = qw/ifDescr ifOperStatus ifAdminStatus ifLastChange/;
my $cmdarg = "public interfaces.ifTable.ifEntry."; # UPDATED to include final "."

for my $ip ( @iplist ) {
    for my $info ( @infolist ) {
        my @pdata = `snmpwalk $ip $cmdarg$info`;

        chomp @pdata;  # remove line-terminations
        s/.* = // for (@pdata);  # remove redundant text

        $ipdata{$ip}{$info} = [ @pdata ]; # create array ref in the hash structure

        $ipdata{$ip}{lastport} = $#pdata; # keep track of how many ports
    }
}

# now print the csv data

for my $ip ( @iplist ) {
    for my $portid ( 0 .. $ipdata{$ip}{lastport} ) {
        my $outstr = '';
        for my $info ( @infolist ) {
            $outstr .= '"' . $ipdata{$ip}{$info}[$portid] . '",';
        }
        $outstr =~ s/,$/\n/; # replace trailing comma
        print O $outstr;
    }
}