Mac OSX 10.5 Upgrade

Apple Online Store
I’ve just finished upgrading my Mac Mini to OSX 10.5, and I have to say, the upgrade could not be simpler. While it did take slightly over an hour to complete, there were fewer than 10 clicks throughout the entire upgrade process, so I can’t imagine how anyone could mung it up. The one detail that I found a little strange was the lack of any indication that the installer was going to perform an “upgrade” install rather than a “fresh” install. Zach simply took it on faith, but I insisted on clicking the “Details” button just to be certain.

The OS itself is quite nice, although it is a bit strange to get used to the finder looking like iTunes. Stacks is a great idea, but part of me wishes it behaved more like a launcher-type application than a different interface to folders. Who knows though. Maybe after using them, I will come to appreciate the feature a lot more.

One thing that I am very glad to see is “Spaces”. Basically virtual desktops, X Windows has had this feature since the very beginning, but it is just now becoming native in Mac OS. Granted, there has almost always been external applications that handle this, but it’s nice to see it wrapped in.

There is a lot of buzz about the “Cover Flow” features that have been added to the finder. I have to admit that it is extremely aesthetically cool and very very slick. How much I use it in my day to day life remains to be seen, but it will be nice to browse documents visually without having to depend only on the title to find them.

Time machine, basically well integrated filesystem snapshots, seems like it will be a wonderful addition, but I have not had the chance to use it yet because I don’t have an external fire wire drive. It’s on my shopping list though, so I will be enabling it just as soon as I have the gear to make it run.

All and all, I think it’s an outstanding upgrade, and well worth the money. Give it a shot… You won’t be sorry.

Recovering From a Corrupt NetInfo Database on OSX.4

I managed to corrupt my NetInfo database on an OS 10.4 server a few weeks ago by not cleanly unmounting the drive after booting from DVD and resetting the admin password. Long story short, this left me with no users on the system at all. With no users, I could not log in to create one, so I had to blow away the NetInfo database and restore it to factory defaults. This should only be done when you only have a small number of users, and don’t mind having to re-create them. Only the user account information is deleted, and the user directory is retained, but you will have to manually add any users you may have back into the system through the GUI, making sure that the new “user” references the old “user’s” account directory.

If you have more than just one or two users, you should use the procedure to recover from one of your NetInfo database backups. A backup of your this database is made at 3:15 every day so long as the computer is running. It is stored in “/var/backups/”, and here are some instructions on how to recover it from it. If, however, you don’t care about re-adding users, and simply want to get into your system quickly, or if you don’t have a backup to restore from, here is how you can do it:


1) Start by booting your Mac into single user mode. To do this, hold down both the “Apple” and the “s” keys as the system boots.

2) The system will have mounted the “/” filesystem read-only to protect against data loss. To get “/” mounted read-write, we have to run two commands:

# /sbin/fsck -fy

# /sbin/mount -uw /

3) Now “/” is mounted read-write, so we can start with the real work. First, rename your existing NetInfo database to something else so the OS will not see it on the way up:

# mv /var/db/netinfo/local.nidb /var/db/netinfo/local.nidb.bad

# mv /var/db/netinfo/network.nidb /var/db/netinfo/network.nidb.bad

4) Next, remove the “.AppleSetupDone” file so the OS will kick you back into the installer upon boot and you can recreate your users.

# rm /var/db/.AppleSetupDone

5) Finally, reboot your system and recreate your users, making sure they are pointed towards their existing account directories.

# reboot

iPhone Hacked; No Longer Bound to AT&T

George Hotz, along with a team of hackers have come up with a method to break the chains binding the iPhone to AT&T, allowing it to be used with any carrier. The complete method can be found here on George’s blog. It does take some soldering skills and a bit of familiarity with UNIX and modem commands it should be pretty easily accomplished by most techies who have some tinkering under their belts.

Even though I still feel the iPhone is too expensive, and that it is lacking in some basic features, this might just be the thing that gets me to buy one. After all, I love hacking hardware!

I heard an interview with Hots on the way home from work Friday. When asked to respond to internet rumors that former phreaker Steve Jobs was mad at him, he said “I want Steve to call me up. Let’s he and I have a man to man about it.” It was wonderful! If Steve Jobs can’t remember his days hacking the phone system and respect Hots and the team for their accomplishments, he truly has lost touch with what hacking is all about.

Wonderful job guys! Congratulations.

RHEL useradd Syntax

Unlike other flavors of UNIX, RHEL does not have a command like adduser which walks you through the process step-by-step, so you have to remember the four flags useradd requires, and in what order it expects to receive them. Since I don’t manually add users unless I’m installing a new server, I don’t run the command enough to remember the syntax… It’s basically the same as it is on Solaris.

useradd -g group -c 'User Name' -d /path/to/home/directory -s /bin/bash username

Example LINUX init Script

From time to time, people want me to create LINUX init scripts for them. I usually just take an existing one for another service and change it up to work for my new application, but most of them have become so long these days that I end up having to hack out a ton of code just to reduce them down to the very basic script I need. I decided to create this very simple template so I wouldn’t have to keep trimming down the more complex scripts that one tends to find in /etc/init.d these days.

This script is chkconfig compatible, so call it the name of your new service and put it in /etc/init.d

The chkconfig: 235 section indicates the the default runlevels. For instance, if we called this script /etc/init.d/new-service and ran chkconfig new-service on, it would be active in runlevels 2,3 and 5.

The 98 and 55 numbers indicate the order of startup and kill. This means that using this tag, the startup symbolic link would be named S98new-service and the symbolic link to kill the process would be named K55new-service.

#### SNIP ####

#! /bin/sh
# Basic support for IRIX style chkconfig
# chkconfig: 235 98 55
# description: Manages the services you are controlling with the chkconfig command

case "$1" in
        echo -n "Starting new-service"
        #To run it as root:
        #Or to run it as some other user:
        /bin/su - username -c /path/to/command/to/start/new-service
        echo "."
        echo -n "Stopping new-service"
        #To run it as root:
        #Or to run it as some other user:
        /bin/su - username -c /path/to/command/to/stop/new-service
        echo "."

        echo "Usage: /sbin/service new-service {start|stop}"
        exit 1

exit 0

#### /SNIP ####

Obviously change all instances of “new-service” to the name of your actual service… Enjoy!

Bash For loop Example

I’m always forgetting the syntax to make “for” loops in Bash. I guess it serves me right for using foreach most of my UNIX life instead. Anyhow, I know I will have to come back here to find it, so I thought I would write put up this quick example with the hope that it will be useful to others as well.

for i in $(seq 1 100); do echo -n "file${i} "; touch file${i} 2>&1; done

The the above for loop will create 100 files (called file1, file2, etc.).

Blank Window When SSH Forwarding X11 Sessions

There are a number of applications running on our servers that have GUI’s that I need to display on the Mac in my office. While the traditional method of exporting the server-side display to my desktop works, it is inherently insecure because the entire session, including any passwords that may be sent are all transmitted in clear-text.

Better to use SSH X11 forwarding. This way the entire session is encrypted and nobody can snoop your passwords. The process of using SSH X11 Forwarding goes something like this:

On the server-side (the machine from which you want to forward the display, make sure this line is in your /etc/ssh/sshd_config file:

X11Forwarding yes

If you had to add it, restart the sshd service.

/sbin/service sshd restart

Now, from the client-side (the machine on which you want to display the forwarded X11 application) connect to the server-side machine with the -X flag. Like so:

ssh -X username@remoteserver

Now you should be able to start X applications and have them display on your client machine through an ssh tunnel. If you are like me, however, some Java applications will not display correctly. Instead of popping up a window with the full application in it, I would only see a totally useless blank window. This frustrated me for months until I found this article at that details how to resolve the problem.

It turns out that all you have to do is put this line in the ssh_config file on your client-side:

ForwardX11Trusted yes

After logging out and back into the server-side machine, everything worked perfectly.