Firefox always starting in offline mode?

I got a new laptop a little over a month ago and ever since the first day I've had an annoying little problem with Firefox. Whenever it started, it was stuck in "work offline" mode. I checked the user prefs in my .mozilla folder, and they said that I should be fine. (There is a setting for starting the browser offline, but it was set to false.)

As with many minor annoyances that don't actually stop me from getting work done, I mostly left the problem alone and just looked it up on Google every so often to see if I could find a solution. Mostly, I only found other Linux users complaining of the problem, but no one who had actually fixed it. Today I saw a fix that seemed unlikely, but I tried it anyway.

sudo apt-get remove network-manager

I didn't really need Network Manager anyway, since it wasn't recognizing my wireless card and I have to use iwconfig on the command line to bring my wireless connection up. And, whaddya know? It works!

From what I've been able to gather, Firefox asks your computer if you are logged into the network, rather than actually trying to connect to a server and then giving up when it doesn't work. Since the network configuration tool that Firefox was talking to didn't know what was really going on with my network connectivity, it gave false information and Firefox "saved me from a 404" by setting the mode to "work offline". How annoying.

This is one of those places where I have to point out to those who want everything to be automatic that we just aren't there yet. There has to be a way for the human to step in and say, "Wo! You got it wrong!" and what the human says should trump what other computer programs are telling you. In Firefox, that could translate into a setting something like "Ignore network manager connection awareness".

If you are a Linux user with this problem and don't want to manage your network through the Linux command line tools like ifconfig, iwconfig and dhclient, I'm afraid I'm not sure what to tell you. There may be another gui network tool you can use, but I am not familiar with any. So, either you'll have to keep un-checking the "work offline" box when you load Firefox, or else you should start reading man ifconfig, man iwlist, man iwconfig and man dhclient.

Sorry I'm not more helpful today.

Kernel driver changes

I learned how to add in or swap out a Linux kernel module today. Kinda cool.

Let's start with the problem. My new laptop has both a wireless card AND an Ethernet card that are incompatible with Ubuntu Linux. So, after a little bit of testing and research, my ever patient friend, savior and all things *nix tutor discovered that the problem was that Ubuntu picks the wrong kernel driver for the Ethernet card on this machine and that it didn't have the wireless driver at all.

Just for extra learning goodness (or kharma or something), after my friend did the whole process to get my networking up and running, the Ubuntu updater updated the kernel and wiped out all his work. That just meant that I got to do the whole process myself, with him reminding me of the steps as I went.

So, the steps: First we downloaded the source code for the drivers. Unpacked the tarballs, followed the directions to compile the drivers.

With one of the drivers, the make install target did the copying of the kernel object into the right place for us. With the other driver, we needed to do that ourselves. To do that we found the ".ko" file in amongst the compiled code and copied it to the correct directory under /lib/modules/.

In the case of the Ethernet card, we needed to blacklist the wrong module as well, just to make sure that it didn't get loaded again by accident. To do that, we headed over to /etc/modprobe.d/blacklist and edited the list to include the bad driver. (Bad, bad driver! Don't come back!!)

Next
depmod -a
runs through your kernel and makes sure that all of the dependencies are there. It takes kind of a long time to run, because it goes through all of your kernel files.

Then use
modprobe [module]
where [module] is the name of your module, of course, to get the driver up and running.

Use
lsmod
to check to see if your modules are there.

We tested the whole thing by creating a boot image with our modified kernel. We did that with
mkinitramfs -o /boot/initrd.img-2.6.27-9-generic.new `uname -r`
and then we created an entry in grub at /etc/grub/menu.lst for the new image. The command mkinitramfs creates a special file with all the kernel information that the system needs to boot. The name that I used was based on the existing file for the pre-modified kernel, but with .new on the end. That was so that we'd know which was which, of course, and so that we'd know what to copy over top of later.

After booting into the modified kernel with out a problem, we went back and removed the extra grub entry, and moved the .new version of the image over top of the normal version. Now the modified kernel is my kernel and I have Ethernet AND wireless networking. Yay!


In case you are wondering, my new laptop is an LG R510. (My 9yo son says the LG stands for "Lawful Good". You think I'm raising a geek?) The drivers it needed are Realtek Ethernet and Ralink Wireless.

Creating a bootable USB disk

With all the MID stuff I've been doing lately, I've had need to create bootable USB disks from img files twice now. As noted previously, I am a dork, so I always forget how to do things like this that I don't do terribly often. To save myself heartache and search time, here are the destructions instructions in short:

1. Get .img file for the OS you need. (via download, Moblin image creator, or whatever)


2. Find out which /dev your USB disk is.


1. before you put your USB disk into the computer, type
   ls /dev/sd*


2. after you put your USB disk into the computer, do that again.
   The new entry is your USB disk


3. Run dd to copy the image to the disk
   sudo dd if=/path/to/imagefile.img of=/dev/yourUSB
   (obviously, you wanna replace those paths with the correct info)

That should do it. It takes a little while, so don't freak out. You can check to make sure it's working by opening another terminal window and running
ls /path/to/usb
where /path/to/usb is the path that you would usually use to see the files on that USB disk. You'll get some gobbeldy gook, but that's fine. It means it's working.

You can get more details at this article on the Intel site.

Wireless connection from the command line

If ever you find yourself stuck with a *Nix box that won't boot into any kind of comfy graphical interface, and you need to connect to a wireless internet connection so that you can look stuff up and maybe solve your problem, here's a helpful tip:

There is a wireless networking utility very much like ifconfig called iwconfig. When you have a chance (and preferably before you really need it) check out the man page for it. Here are some quick and dirty instructions, in case you are desperate right now.

To find out what wireless networks are available to you, type
iwconfig wlan0 scan (see comments)
iwlist wlan0 scan

To attach to an open, non-encrypted network, type
iwconfig wlan0 essid netname
where netname is the essid of the network you want to connect to.

If you only have encrypted networks available, you might be in a bit more trouble. I haven't actually managed to get that working at all yet, though theoretically, it should work something like this:
iwconfig wlan0 key s:password
iwconfig wlan0 essid netname
where password is your password and netname is the essid of the network you want. The s: means that the password is in string format. If you know the hex version of your password, then instead of saying s:password you'd just type in the hex of the password like this:
iwconfig wlan0 key 0123-4567-89

Good luck getting your GUI fixed!

Woops! MySql didn't start when the server rebooted!

One of my customers had this problem today. I got a text message, "Lisha! Can you look at the server and tell me why mysql isn't working? I rebooted the server and now the website has an error. Something about Error #2002 and the mysql.socket."

It turned out that when they rebooted their LAMP server, the mysql demon didn't turn on with the rest of the services like the apache http demon. Luckily, this is easy to fix. I ssh'd to their server and got to work.

First, I checked to see if my hunch was right:
mysqladmin ping
mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)'
Check that mysqld is running and that the socket: '/var/lib/mysql/mysql.sock' exists!

Yipes! Yup, you have no bananas (or mysql, as the case my be).

Next, I ran the mysql initialization script:
/etc/init.d/mysqld start
Starting MySQL: [ OK ]

Then check to see if it worked:
mysqladmin ping
mysqld is alive

Ah, yes. All better!


Next time, we can make mysql demon startup at boot time. On a Red Hat type system you can run the following code as root (or via sudo) to run the initialization script automatically at boot:
ln -s /etc/rc.d/init.d/mysqld /etc/rc.d/rc3.d/S98mysql

Creating A New *Nix User

The easiest way to create a new user on the command line is:
sudo useradd george
sudo passwd george

But that's not always enough. Let's say, for instance that you want people to change their password the first time that they log in and then again every three weeks. Let's set georgette up like that:
sudo useradd georgette -c "Georgette Userina"
sudo passwd georgette
(give her a throw-away password)
sudo passwd -e -x 21 georgette


Here's what we just did:
sudo = "superuser do" (do this as if you are root)
add user georgette with the comment (-c) "Georgette Userina" (-c is usually used for the user's full name)
give georgette a password she can use the first time she logs in
expire georgette's password immediately (so she has to change it when she next logs in) and then expire (-x) her password every 21 days.

Need a short term user? Maybe you have a contractor working with your company for a short time or a friend that's hanging out at your house for the next two weeks and needs access to your Ubuntu desktop while he's there. Here's how to do it:
sudo useradd sammi -c "Sammi Shortimer" -e 2008-03-10


Here we use the -e option with useradd to expire the account after March 10, 2008.

If you do most of your new user adds with the same special options, you can set those things as default in the file /etc/login.defs

Give a user a new group

So, you have someone who just got a new position within your organization and now s/he needs additional permissions on the server. It makes more sense to give people permissions based on their position rather than on their user. That way, you can give and take exactly the right group of permissions for the position based on a well thought out policy rather than a spur of the moment, "I think they need x to get things done today," sort of thing.

A perfect example of this is sudoers privileges. You can give specific root-type abilities to users or groups of users in the /etc/sudoers file. Another example of this is when you make a certain folder owned by a specific group and have people write to it as *themselves.thatGroup.

You want to use usermod to add a new group to a user, but the problem is that when you use -G to add additional groups, it takes the list that you give it and erases whatever was on the list before. The solution is to add -a for append like this:

usermod -G groupname -a username

Now your user won't lose any of the old groups s/he had, but s/he will get the new one that they need.

*NB: There are a couple of notations for username and groupname for ownership on *Nix. One is username.groupname. The other is username:groupname They are often interchangeable on a single OS or distro, but sometimes you can only use one or the other for commands like chown.

Cups Printing from the Command Line

Sometimes you just need to print something without going into an application. Here's how...

First, find out what printers are available
lpstat -a

That will tell you what printers are available to you. Then you can print to one of them
lpr -P [printer_name] [file_name]

Need to find out what jobs are running right now?
lpstat -o
(that's the letter oh, not the number zero)

Need to cancel a job?
lprm [job_id]

For more information and all sorts of other CUPS goodness, check http://www.cups.org

Oh How I Hate Command Line Tar

It's cuz I'm dyslexic and I always get things backwards. Which comes first? The file I'm trying to create or the one I'm trying to tar up? Here's the answer for future reference.


tar -cf [the file you want to create] [the file(s)/directory(ies) you want to tar]


The "c" stands for "create". The "f" stands for "file" (the default is to pipe the tarred stuff to stdin). You can also turn it into a gzip file in the same go with the letter "z" or into a b-zip file with the letter "j".

Something of note: man tar actually gives useful examples, unlike most man pages which give information but no examples to help the slow of brain (like me).

Here are some examples from the man page as it lives on our office Web servers which are running CentOS Linux:

EXAMPLES
tar -xvf foo.tar
verbosely extract foo.tar

tar -xzf foo.tar.gz
extract gzipped foo.tar.gz

tar -cjf foo.tar.bz2 bar/
create bzipped tar archive of the directory bar called
foo.tar.bz2

tar -xjf foo.tar.bz2 -C bar/
extract bzipped foo.tar.bz2 after changing directory to bar

tar -xzf foo.tar.gz blah.txt
extract the file blah.txt from foo.tar.bz2