Category: Reliable Penguin

Perl – Sort associative array by value

July 8, 2009

Here’s an alpha sort of the values of the associative array named “myarray”:

foreach my $key (sort {$myarray{$a} cmp $myarray{$b}} keys %myarray) {
        print "$key : " . $myarray{$key} . "\n";
};

foreach my $key (sort {$myarray{$a} cmp $myarray{$b}} keys %myarray) {

print "$key : " . $myarray{$key} . "\n";

};

And here’s the same sort numerically:

foreach my $key (sort {$myarray{$a} <=> $myarray{$b}} keys %myarray) {
        print "$key : " . $myarray{$key} . "\n";
};

foreach my $key (sort {$myarray{$a} <=> $myarray{$b}} keys %myarray) {

print "$key : " . $myarray{$key} . "\n";

};

And if you want numeric descending:

foreach my $key (sort {$myarray{$b} <=> $myarray{$a}} keys %myarray) {
        print "$key : " . $myarray{$key} . "\n";
};

foreach my $key (sort {$myarray{$b} <=> $myarray{$a}} keys %myarray) {

print "$key : " . $myarray{$key} . "\n";

};

Of course don’t forget how to sort keys:

foreach my $key (sort keys %myarray) {
        print "$key : " . $myarray{$key} . "\n";
};

foreach my $key (sort keys %myarray) {

print "$key : " . $myarray{$key} . "\n";

};

And a numerical sort of keys:

foreach my $key (sort {$a<=>$b} keys %myarray) {
        print "$key : " . $myarray{$key} . "\n";
};

foreach my $key (sort {$a<=>$b} keys %myarray) {

print "$key : " . $myarray{$key} . "\n";

};

Remote access via ssh with RedHat Rescue Disk

July 7, 2009

Insert Rescue Disk and boot server. At the first prompt type “linux rescue” and hit enter. Follow boot disk prompts to start networking. Enter the system’s ip address, netmask, gateway and name server. Continue with prompts until the root partition is mounted and you get a command prompt. Verify network configuration with ifconfig and route. Use the following commands to start sshd:

cd /mnt/sysimage
chroot /mnt/sysimage
mount /dev/pts
/sbin/service sshd start

cd /mnt/sysimage

chroot /mnt/sysimage

mount /dev/pts

/sbin/service sshd start

You should now be able to SSH into the server.

MS-SQL 2000 : Truncate transaction log

June 17, 2009

Execute the following commands:

DBCC SHRINKFILE(pubs_log, 2)
BACKUP LOG pubs WITH TRUNCATE_ONLY
DBCC SHRINKFILE(pubs_log,2)

DBCC SHRINKFILE(pubs_log, 2)

BACKUP LOG pubs WITH TRUNCATE_ONLY

DBCC SHRINKFILE(pubs_log,2)

This will reduce the transaction log for the “pubs” database to 2MB.

LFTP mirror script

May 13, 2009

Here’s a very handy script to mirror a site via ftp with lftp:


#!/bin/bash

lftp -c 'open -e "set ftp:list-options -a; mirror -a --parallel=10 -v fromdir/ ./todir" -u user,pass host'

#!/bin/bash

lftp -c 'open -e "set ftp:list-options -a; mirror -a --parallel=10 -v fromdir/ ./todir" -u user,pass host'

And here’s a mirror in the opposite direction:


#!/bin/bash

lftp -c 'open -e "set ftp:passive-mode false; set ftp:list-options -a; mirror -a --parallel=1 --reverse -v  fromdir/ ./todir" -u user,pass host'

#!/bin/bash

lftp -c 'open -e "set ftp:passive-mode false; set ftp:list-options -a; mirror -a --parallel=1 --reverse -v fromdir/ ./todir" -u user,pass host'

Making Plesk More PCI Complient

May 11, 2009

Here’s a great article that describes some of the things that can be done to make a plesk server pass PCI compliance scans: http://www.linux-advocacy.org/web-servers/making-plesk-more-pci-compliant