system admin

How to extract original kexts from OS X install image

If you accidentally delete or modify a kext this method will help you restore it. The easiest way is restore from TimeMachine backup.
If you do not have any backup...

1. Download the Mavericks image from App Store
2. Install Pacifist from CharlesSoft
3. Open with Pacifist:

/Applications/Install OS X Mavericks.app/Contents/SharedSupport/OSInstall.mpkg

4. Find and select Extensions folder:

Blog categories:  Unix admin

Change you uid bellow 1000 on Ubuntu 14.04

You need to login as root first in command line mode (CTRL+ALT+F1). If the root user has no password, use

sudo passwd root

to set new password.

This command chnages uid of youruser to 501:

usermod -u 501 youruser

This changes gid of youruser group to 501:

group mod -g 501 youruser

Only the first command changed your files uid in your home. So the best you can do is execute this command:

Blog categories:  Linux  Unix admin

How to convert your real system to virtual machine?

I had a real Linux server system that I need to convert into virtual server, because I wanted to sell my old hardware, but I needed the system as backup. This backup is able to run as virtual server. This is a very useful backup method. This tutorial show you how you can convert your whole system into virtualbox system. Virtualbox is a free opensource virtual computer solution from Oracle.

1. Backup your system disk

If you can, put your system disk to another computer. But if you can't do it you can do it the original system.

SATA HotPlug and HostSwap in Ubuntu Linux

Check active scsi devices:

ubuntu@ubuntu:~$ lsscsi
[1:0:1:0]    disk    ATA      SAMSUNG HD103SJ  1AJ1  /dev/sda
[2:0:0:0]    disk    ATA      SAMSUNG HD103SJ  1AJ1  /dev/sdb
[3:0:0:0]    cd/dvd  HL-DT-ST DVDRAM GH22NS90  HN00  /dev/sr0
[5:0:0:0]    disk    Generic  STORAGE DEVICE   9451  /dev/sdd
[6:0:0:0]    disk    GT-I5700  - Card                /dev/sdc

Now refresh SCSI devices. Use this command to refresh host0 (or host1, host2, host3):

ubuntu@ubuntu:~$ echo "- - -" | sudo tee -a /sys/class/scsi_host/host0/scan 

Check the result:

SSH port forwarding in nutshell

My goal:
I want to see the intranet website from home with my linux laptop. I can connect over SSH to the intranet web server. But I want to see the webpage in a browser of my laptop.

The solution is SSH port forwarding. From my Linux laptop. Here is the syntax:

ssh -L <myPortNumber>:<RemoteIP>:<RemotePort>  <host> [other ssh options like port and user]

I used this:

ssh -L 8088:  intranetserver.example.com

Now I can click to http://localhost:8088/ on my favorite browser and I can browse the intranet.

Blog categories:  Linux  Unix admin

RMagick install on Ubuntu 10.10 and 10.04

This small tutorial work on Ubuntu Hardy (8.04), Lucid 10.04 and Maverick (10.10)

Install Imagemagick and GraphicsMagick

apt-get install imagemagick graphicsmagick

Install Image Magick development files

apt-get install libmagickcore-dev libmagickwand-dev
gem install rmagick

On Hardy:
Install imagemagick from source and after it install development files:

Blog categories:  Linux  Unix admin

How to install Phusion Passenger for ruby 1.9.2

There are some easy steps to install Phusion Passenger for ruby 1.9.2 and apache2 on Ubuntu Linux.

1. Install rvm system wide

sudo bash < <( curl -L http://bit.ly/rvm-install-system-wide )

2. Install ruby 1.9.2

rvm install 1.9.2

3. add new line in /etc/bash.bashrc

[[ -s /usr/local/lib/rvm ]] && . /usr/local/lib/rvm

4. install passenger

sudo -i # you need root shell
rvm use 1.9.2-p0@global # or your version, use: rvm list