I assume that the format of the ifconfig -a output will always be the same; that is, interface followed by interface information. If that is the case, then the following code sample will work for you. NOTE:
1) the output of ifconfig -a has been stored in a file
2) the interface information is stored in a hash where the interface name is the key and its status is the value.

#!/usr/bin/perl
use strict;

my ($if, %hash, $key);
open(FILE, "<f.txt");

while(<FILE>) {
    chomp $_;
    ($if = $_) =~ s/^(\w+?):.+/$1/ if $_ =~ m/^\w+:/;
    ($hash{$if} = $_) =~ s/.+status:\s+(.+)/$1/ if $_ =~ m/status/;
}

close(FILE);

foreach $key (keys %hash) {
    print "$key: $hash{$key}\n";
}

exit;
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hope this helps,
davidj