use strict;
use warnings;
use Data::Dump;

my $first = 'dev';
my $last  = 'manage';
my $in    =  0;
my @keys;

while (<DATA>)
{
    if (defined(my $key = (split)[-1]))
    {
        if ($key eq $first .. $key eq $last)
        {
            $in = 1;
            push @keys, $key;
        }
        elsif ($in && $key eq 'manage')
        {
            push @keys, $key;
        }
        else
        {
            $in = 0;
        }
    }
}

dd @keys;

__DATA__
< as before >