Neohexa » Linux

Delete all messages in Postfix queue

admin — Mon, 14 Nov 2011 19:10:24 +0000

for i in `mailq|grep '@' |awk {'print $1'}|grep -v '@'`; do postsuper -d $i ; done

Why I gave Ubuntu the boot

admin — Tue, 25 Oct 2011 18:39:01 +0000

Default installed applications.
Automatic inclusion of “Ubuntu One”.
Empathy. Empathy. Empathy.
Unity. Especially since Gnome Classic is no longer an option in 11.10 forward.
Plymouth. I get that it tries to give a nice graphical boot, but I don’t think I’ve ever seen it work seamlessly. Also, purple.
Insane metapackages.
Slow boot.
Themes. Who is in charge of the color palette for these themes? Seriously?
Server Edition: Can we get the configuration questions entirely out of the way in the first part, so the system can complete the install on it’s own, without having to come back to it every 5-10 minutes to answer a question?

Arch Linux, Quick First Impression

admin — Tue, 25 Oct 2011 18:06:46 +0000

Five minute install with net-install CD for base system.
Very fast boot (5 secs to login tty, 10 seconds to D.E.)
~2GB required for customized, fully functional system with D.E. and Compiz
Does not force optional dependencies to be installed
Well documented
Lean, no bloat
Extremely up to date packages, 3.0 kernel

To be continued..

Change I.P. address on Ubuntu Server

admin — Thu, 13 Aug 2009 14:37:42 +0000

sudo pico /etc/network/interfaces
If your device name is eth0, the configuration block should look like the following-

iface eth0 inet static address 192.168.1.110 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255 gateway 192.168.1.1 dns-nameservers 208.67.222.222 208.67.220.220 127.0.0.1

If you wish to add another I.P. address, you can add a block similar to this-

iface eth0:1 inet static address 192.168.1.111 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255 gateway 192.168.1.1

All that is needed now is a restart of networking-

sudo /etc/init.d/networking restart

Downgrade MySQL 5.x to MySQL 4.x on Ubuntu Server

admin — Tue, 28 Jul 2009 18:29:36 +0000

If you ever need to downgrade from MySQL 5.x to MySQL 4.x (hope you don’t), chances are you are going to run into a problem with apt-get. You will most likely receive cryptic, unhelpful dpkg errors.

If this is the case, try the command below.

sudo aptitude purge mysql-common mysql-client mysql-server && sudo aptitude install mysql-server-4.1 mysql-client-4.1

This should purge whatever is left of the MySQL 5.x installation, and then install the MySQL 4.x version. If this fails, proceed to bang head against nearest hard object.

Tuning Swap Usage with Linux

admin — Tue, 28 Jul 2009 14:35:57 +0000

Those of you with lots of RAM could benefit from this tweak. There is a value controlled by sysctl called “vm.swappiness”. This is a value from 0-100 which tells the system how aggressively to use the swap space on your system.

Setting this value to 0 will tell the system to avoid writing anything to swap if at all possible, and a value of 100 will have your system almost immediately write out your memory to a swap file.

The default on Ubuntu and most other Linux systems is 60. If you don’t have more than 1GB of RAM I would not recommend altering this value. On my workstations with 2GB of RAM or more I usually go 10 or 0.

To set the swappiness value:

sudo sysctl vm.swappiness=10

To make the change stick after reboots, edit /etc/sysctl.conf with your favorite editor, and add the line “vm.swappiness=10″ if it does not already exist.

Dear Adobe

admin — Wed, 22 Jul 2009 15:04:21 +0000

Please make a version of your flash player for Linux that doesn’t totally blow. Thank you, that is all.

Since we’re on the subject, could we also move a little faster with the HTML5 + Ogg video?

Quick and Dirty IP Scan

admin — Mon, 20 Jul 2009 18:13:22 +0000

Here’s a quick, dirty, and not 100% reliable command to tell you which IPs in a range are in use:

nmap -sP 192.168.1.1-254

The above example will scan the range of 192.168.1.1 – 192.168.1.254, and will give you a result something like this:

Host (192.168.1.1) appears to be up. Host (192.168.1.2) appears to be up. Host (192.168.1.14) appears to be up.

Corrupt InnoDB Fix

admin — Tue, 14 Jul 2009 18:47:36 +0000

If MySQL won’t start due to corrupt InnoDB tables, you can add
[mysqld] innodb_force_recovery = 4
to the /etc/my.cnf file, and restart MySQL. This will allow MySQL to start even with the corrupt InnoDB tables. I’m not quite sure if this fixes the tables or merely allows MySQL to run despite the warnings.

More Info

List Installed Packages w/ Ubuntu

admin — Tue, 14 Jul 2009 17:26:00 +0000

This trick comes in real handy if you need to reinstall your Ubuntu/Debian system, or install your preferred software automatically with a fresh install.

From the system with your desired software:

dpkg --get-selections > mysoftwarelist.txt

To the reinstalled or fresh system:

dpkg --set-selections mysoftwarelist.txt

sudo dselect