Linux Blog

If you follow me on Twitter you would know I asked everyone if there was anything that they wanted me to write about. @Ben_Marvin responded and asked about logging the commands you type to Twitter.At first, I thought that this could be done with history, which it probably can be, but does everything you type really have to be echo’ed to Twitter? I don’t think that you’d have many friends, Twitter would probably hate you and you’d most likely hit your maximum requests per hour pretty quickly.The Script command is another option, and this works quite well for this purpose. Read the script man page to find out more about this program. It basically (when ran) takes the I/O from your terminal and logs it to a file. Its a very handy utility.So, how do we get this data into Twitter? First of all, Twitter doesn’t allow very long posts so echoing out the data that the commands you type is not really practical. The best way to do it is to use script to log the session, exit the session and grep for the “]0\;” string for stuff you typed & not the responses.Here is the code:

script; grep ]0\; typescript 

You can then copy and paste it to your favorite Twitter application or pipe it to a scrubbing script to remove the formatting and do the correct HTML stuff, then post it via the http interface. Either way, it can be done even though I don’t think it really should.

TheLinuxBlog.com was intended to be a blog where I could log my thoughts, findings and generally keep track of how to do stuff. Since it was started this is still the goal. Ultimately I’d like to refer to TheLinuxBlog on how to do something just as much as I refer to google for everything else. That being said, one thing that recently came up for me was “How do I change my desktop on Fedora”.

I had done this before but I couldn’t remember the command to do so. Well, since this blog is as much for me as it is for the reader I figure I can post the how to here and kill two birds out with one blog post, I mean stone.

The program I use to change my window manager on Fedora is: switchdesk.

Switchdesk can be installed by Yum or if you installed Fedora from DVD or CD and didn’t fine tune your packages then you probably have it already. All you have to do to run it is type:

switchdesk

Now, if you are in an X session you will get a nice graphical dialog that will help you change your desktop manager. If your at the terminal it will exit and ask you nicely to type either gnome, kde, xfce or any other window manager you may have installed.

Don’t ask me why every distribution has a different named command and interface to achieve the same thing thats just the way it is. Maybe one day I’ll get a list of all of the commands and post them. Alternatively if anyone wants to start a list feel free to post them in comments or by e-mail.

Using proprietary software to some Linux users is considered a sin, right up there with not reading the manual. Not everyone that runs Linux feels this way. I for one don’t mind using a commercial / propriety product if the product serves the purpose well, and perhaps better than an open source implementation.

Take VMWare server for example. Although it does have its problems, it works very well for virtualization. Its pretty stable, has a good interface, works well and most of all is free. I have no problem installing and using this as long as it works.  I’ve been using it for a while, its what I’m used to and I have no problems with it. The moment VMWare Server stops working, I’ll try to find another alternative. Be it open source or not.

I don’t get why some people are so into the open source movement. Not tainting a system to me has no clear advantages. If I were to not install any proprietary software I would hardly be able to use my Linux box. Think about it, no Java (ok, I’d have the IcedTea runtime and GCJ), but no supported Java for Tomcat / Eclipse, I’d have no Flash, hardly any video codecs and no 3D accelerated graphics. My virtualization, may or may not work depending on what day of the week it was or if I had supported hardware. There is probably a whole lot more that I am missing that I don’t even know about.

So, I’m just interested to know what is every one else’s take on using proprietary software? Am I alone in being “fine” with installing closed source / proprietary software? Is my computer going to go to robot hell and sing with Bender for eternity? Please let me know your thoughts.

Yakuake - “Pronunciation Key: yuh-kweyk”

Yakuake is a terminal emulator for KDE
“Why do we need another terminal emulator?”
I hear you ask.

Well, the Yakuake terminal emulator resembles the terminal from Quake (hence the name), except the only thing that gets owned when you run Yakuake is your to-do list.

Have you ever been fragged in Quake because you hit the Tilda key by accident?
Ever used this to your advantage while playing two player by pressing your opponents tilda key?

Have no idea what I’m talking about?
envision a terminal that magically pops up when you press a shortcut, hides when your not using it but retains the output / processes and does not show up in the task bar.

Sure there are old school ways of achieving the same thing, but Yakuake is convenient. It is based on Kommander so its highly configurable and customizable but it works right out of the package.

I use it on most of my machines and for quick tasks I find myself using a regular xterm less. If you want a quick easy access to a terminal I’d recommend trying Yakuake out, take a look at all of the keyboard shortcuts and see if there is any way you can make it work better for you.

I have my keyboard shortcuts set up so I can add new sessions, close sessions, rename sessions, move sessions and resize the terminal. It works great with the switch to session shortcuts that I also set up.

Its in the Fedora repositories, I’m sure its included in Debians 18,000 or so packages and probably Gentoo’s too, so give it a shot!

I’ll see what I can do about a video tutorial in the future to demonstrate the power of Yakuake.

If you run into the following problem:

VMware Server is installed, but it has not been (correctly) configured
for the running kernel. To (re-)configure it, invoke the
following command: /usr/local/bin/vmware-config.pl.

and then try to issue the vmware-config.pl command and get something similar to the following:

/tmp/vmware-config1/vmnet-only/bridge.c: In function ‘VNetBridgeUp’:
/tmp/vmware-config1/vmnet-only/bridge.c:949: error: implicit declaration of function ‘sock_valbool_flag’
make[2]: *** [/tmp/vmware-config1/vmnet-only/bridge.o] Error 1
make[1]: *** [_module_/tmp/vmware-config1/vmnet-only] Error 2
make[1]: Leaving directory `/usr/src/kernels/2.6.25.10-47.fc8-i686′
make: *** [vmnet.ko] Error 2
make: Leaving directory `/tmp/vmware-config1/vmnet-only’
Unable to build the vmnet module.

Then try to use the VMWare any patch from: http://groups.google.com/group/vmkernelnewbies/files
I had used the patch before to get my VMWare Server up and running but did not realize that you had to use the patch after kernel upgrade or your VMWare server will no longer work.

Who knew?

Yum stands for “YellowDog Updater Modified”

Yum is a standard way to update multiple distributions.

The openSUSE build repository uses the yum updating system

Yum was written in Python.

If you install the yum-utils package you can download yum rpm packages by running:

yumdownloader –source yum

There are graphical front ends to YUM

Yum is maintained by the Linux@Duke project, thats right the basketball team you love to hate: The Blue Devils.

Changing virtual terminals is almost essential for the Linux system administrator. If you don’t know what I mean by this then try pressing CTRL+ALT+F5 once you are there press CTRL+RIGHT ARROW until you get back to your display (should be two or so times depending on your distribution)

Until a few minutes ago I didn’t know that this could be done by the command line. chvt is a nifty command to change virtual terminal. Basically all you have to do is type “chvt 2″ to change to tty2. I found it while I was looking for a solution to open up a view of other active terminals.

This could be handy if your on a laptop or your function keys are missing / broken.

I decided not to go ahead and purchase an iPhone just yet. What that means is I will not have a need for a SSH client. Once I get an iPhone its my first thing to do. The client would probably be released for free, or with optional support / donation.

So,  if there are any companies or organizations that need an iPhone SSH client, consider sponsoring the development in the form of an iPhone. In return I will give the community a free SSH / SCP client and that the donor free lifetime support.

This post is an update to: http://www.thelinuxblog.com/iphone-ssh-client/

I don’t keep up with releases of new Linux distributions really. If I did then I probably wouldn’t have time to write on this blog, but I noticed that Gentoo was released on Sunday the 6th of July (http://www.gentoo.org/news/20080706-release-2008.0.xml) I’ve never been a big Gentoo guy, I’ve dabbled with it but it never really caught my attention. I think it may be time for me to revisit Gentoo, at least in a virtual environment to check it out again. I do have a need for a small footprint, easy to maintain and expandable operating system. I have been using Slackware for simplicity and small footprint, but it is not the easiest to maintain or expand. Gentoo on the over hand can be configured well, updates easily and is pretty expandable through portage and emerge. The only thing that concerns me is the compile time, often the reason I want a minimal installation is for a project that has to run on less than adequate hardware. Using Gentoo rather than another distribution could be a problem since it seems like it takes for ever to install by copying and extracting files, let alone compile them.

Anyhow, have fun with the new Gentoo!

Fedora is a great desktop system, it has a pretty good services manager called service. It can be used to turn on, off and restart most services that run on the system. Should you want to manage running services all you have to do is type:

service <service name> <stop | start | restart>

If you don’t know the service name it can normally be found by issuing the –status-all switch. Doing so will output a long list of services so you may want to grep it or use a pager such as less:

[root@linux-blog ~]# service –status-all | less

[root@linux-blog ~]# service –status-all | grep snmp
capi not installed - No such file or directory (2)
JAVA_EXECUTABLE or HSQLDB_JAR_PATH in ‘/etc/sysconfig/hsqldb’ is set to a non-file.
snmpd is stopped
snmptrapd is stopped

While service is a great utility to manage services it does not stop them from running at startup. To manage services that start up when you boot you can use a handy little dialog script called “ntsysv”:

[root@linux-blog ~]# ntsysv

This will give you a nice dialog which is intuitive and similar to those of text based installers. Select the services you want to start up and then tab over to OK. I turn a lot of services off that I don’t use, if you’re unsure of what you need, try stopping it with the services command first and see if anything breaks. If after test it works well just turn it off.

Since I don’t use SELinux on my development machine, I always turn off setroubleshootd. I used ntsysv to stop it from starting at bootup and if I need it I can use the service command to start it.

Here is a screenshot of ntsysv in action:

Have you ever wanted to make a command for something that did not exist? Perhaps modify the functionality of a particular application to something more suitable? I know I have. For example, and I know that there is probably a better way to do this, but on certain Linux machines (such as servers), I like to clear the output before exiting. While I can type the command:

clear; exit

this still leaves me with a line at the top of the screen. Some distributions clear this automatically, for those that don’t an alias can be used.The basic principal for a bash alias is easy. You set an alias up and then use that alias instead of the command.
It appears that aliases have precedence over any already existing applications in the path so it becomes handy if you wish to override a command or perform a task before launching a built in command. I’m sure that this option can be changed if needed.

Now you know what aliases are here is how to use an alias to override the exit command in bash.

alias exit=”clear; exit > /dev/null 2> /dev/null”

Aliases with parameters can get tricky, the best workaround I have found is to write a shell script and put it in your local bin directory.