sunsplash:~# ls -l /home/grad/c
total 28
drwx------    3 angelop  employee     4096 Jan 10 17:23 abunting
drwx------    3 angelop  employee     4096 Jan 10 17:23 aer
drwx------    3 angelop  employee     4096 Jan 10 17:23 alison3
drwx------    3 angelop  employee     4096 Jan 10 17:23 alitvak
drwx------    3 angelop  employee     4096 Jan 10 17:23 angelad
drwx------    3 angelop  employee     4096 Jan 10 17:23 angelop
drwxr-xr-x    3 root     root         4096 Jan 10 17:23 anistasi
sunsplash:~# ls -l /home/grad/c
total 48
drwx------    3 bookoff  misc         4096 Jan 10 17:23 abunting
drwx------    3 anistasi employee     4096 Jan 10 17:23 aer
drwx------    3 anistasi employee     4096 Jan 10 17:23 alison3
drwx------    3 anistasi employee     4096 Jan 10 17:23 alitvak
drwx------    3 bookoff  misc         4096 Jan 10 17:23 angelad
drwx------    3 anistasi employee     4096 Jan 10 17:23 angelop
drwx------    3 anistasi employee     4096 Jan 10 17:23 anistasi
drwx------    3 anistasi employee     4096 Jan 10 17:24 asantili
drwx------    3 anistasi employee     4096 Jan 10 17:24 banfield
drwxr-xr-x    3 root     root         4096 Jan 10 17:24 bbatke
drwxr-xr-x    3 root     root         4096 Jan 10 17:24 bigdaddy
drwxr-xr-x    3 root     root         4096 Jan 10 17:25 bookoff
sunsplash:~# ls -l /home/grad/c
total 48
drwx------    3 bookoff  misc         4096 Jan 10 17:23 abunting
drwx------    3 bigdaddy employee     4096 Jan 10 17:23 aer
drwx------    3 bigdaddy employee     4096 Jan 10 17:23 alison3
drwx------    3 bigdaddy employee     4096 Jan 10 17:23 alitvak
drwx------    3 bookoff  misc         4096 Jan 10 17:23 angelad
drwx------    3 anistasi employee     4096 Jan 10 17:23 angelop
drwx------    3 anistasi employee     4096 Jan 10 17:23 anistasi
drwx------    3 anistasi employee     4096 Jan 10 17:24 asantili
drwx------    3 anistasi employee     4096 Jan 10 17:24 banfield
drwxr-xr-x    3 root     root         4096 Jan 10 17:24 bbatke
drwxr-xr-x    3 root     root         4096 Jan 10 17:24 bigdaddy
drwxr-xr-x    3 root     root         4096 Jan 10 17:25 bookoff


##</code><code>##

#!/usr/bin/perl -w

use strict;
use lib "/home/qiang/source";
use Parallel::ForkManager;

my $source = "/home/sta/";
my $target = "/home/grad/";
my @source_topdirs = map {$source . $_} ('a'..'z');
my @target_topdirs = map {$target . $_} ('a'..'z');

my $maildir = "Maildir";
my $convert_script = "/home/qiang/m.pl";
my $max_proc = 5;
my $pm = new Parallel::ForkManager($max_proc);

my $start = scalar localtime(time);

foreach my $source_topdir ($source_topdirs[2]) {

    # usr names under /home/sta/[a-z]
    my @usr_names = map {chomp;$_} `ls $source_topdir`;
    # /home/grad/[a-z]
    my $target_topdir = $target_topdirs[2];

    foreach my $usr_name (@usr_names) {
        my $source_usrdir = $source_topdir . "/" . $usr_name;
        my $target_usr_maildir = $target_topdir . "/" . $usr_name . "/" . $maildir;

print "working on $source_usrdir \n";

        $pm->start and next; # do the fork
        # prepare new user mail dir and convert old user dir into it.
        # &mkdirs_and_convert($target_topdir,$source_usrdir,$target_usr_maildir);

    my ($uid,$gid) = (stat $source_usrdir)[4,5];
    #print "uid: $uid  gid: $gid source: $source_usrdir target: $target_topdir\n";

    `/bin/mkdir -p $target_usr_maildir &&
         $convert_script -s $source_usrdir -R -d $target_usr_maildir &&
              /bin/chown -R $uid:$gid $target_topdir &&
                            /bin/chmod -R 0700 $target_topdir`;


        $pm->finish;
    }
}
$pm->wait_all_children;