Here’s a quick way to get the latest updates on your PC using the command line if you are using Ubuntu or Debian:

sudo apt-get update && sudo apt-get upgrade

Of course, you can split these commands up if you prefer to look before you leap. At the very least least, it’s so much slicker than the GUI route.

Here’s a piece of Linux/UNIX shell scripting code that will do a recursive FTP refresh of a website for you:

lftp <<~/Tmp/log_file.tmp 2>>~/Tmp/log_file.tmp

open ${HOSTNAME}

user ${USER} ${PSSWD}

mirror -R -vvv “${REP_SRC}” “${REP_DEST}”

EndFTP

When my normal FTP scripting approach left me with a broken WordPress installation and an invalid ticket in the project’s TRAC system that I had to close, I turned to looking for a more robust way of achieving the website updates and that’s what led me to seek out the options available for FTP transfers that explicitly involve directory recursion. The key pieces in the code above are the use of lftp in place of ftp, my more usual tool for the job, and the invocation of the mirror command that comes with lftp. The -R switch ensures that file transfer is from local to remote (vice versa is the default) and -vvv turns on maximum verbosity, a very useful thing when you find that it takes longer than more usual means. It’s all much slicker than writing your own script to do the back-work of ploughing through the directory structure and ensuring that the recursive transfers take place. Saying that, it is possible to have a one line variant of the above but the way that I have set things up might be more familiar to users of ftp.

In previous posts, I have talked about getting VMware Workstation back on its feet again after a kernel upgrade. It also seems that VirtualBox is prone to the same sort of affliction. However, while VMware Workstation fails to start at all, VirtualBox at least starts itself even if it cannot get a virtual machine going and generates errors instead.

My usual course of action is to fire up Synaptic and install the drivers for the relevant kernel. Looking for virtualbox-ose-modules-[kernel version and type] and installing that usually resolves the problem. For example, at the time of writing, the latest file available for my system would be virtualbox-ose-modules-2.6.24-19-generic.  If you are a command line fan, the command for this would be:

sudo apt-get install virtualbox-ose-modules-2.6.24-19-generic

The next thing to do would be to issue the command to start the vboxdrv service and you’d be all set:

sudo /etc/init.d/vboxdrv start

There is one point of weakness (an Achilles heal, if you like) with all of this: the relevant modules need to be available in the first place and I hit a glitch after updating the kernel to 2.6.24-20 when they weren’t; I do wonder why Canonical fail to keep both in step with one another and why the new kernel modules don’t come through the updates automatically either. However, there is a way around this too. That means installing virtualbox-ose-source via either Synaptic or the command line:

sudo apt-get install virtualbox-ose-source

The subsequent steps involve issuing more commands to perform a reinstallation from the source code:

sudo m-a prepare

sudo m-a auto-install virtualbox-ose

Once these are complete, the next is to start the vbox drv as described earlier and to add yourself to vboxusers group if you’re still having trouble:

sudo adduser [your username] vboxusers

The source code installation option certainly got me up and running again and I’ll be keeping it on hand for use should the situation raise its head again.

In Windows, it’s a matter of right-clicking on the folder and looking in its properties. I am sure that there is a better way of doing it in that ever pervasive operating system but, in the worlds of Linux and UNIX, the command line comes to the rescue as it is wont to do. What follows is the command that I use:

du -sh foldername

The s option makes it present the total space taken up and leaving it out gets you a breakdown of how much space the subfolders are taking up as well. The h makes the sizes output more friendly to human eyes with things like 10K, 79M and 51G littering what you get. The command itself is a much shorter way of saying “print disk usage”. It’s all quick and easy when you know it and very useful in this age of ever increasing data volumes.

Here’s the command that does the deed for me on Ubuntu:

uname -a

I usually only need it to find out what header files I need for any VMware repeat installations or reconfigurations.

One of the nice things about the Linux/UNIX command line is that you get the options of stringing together a number of commands on one line for submission of all for processing at one go. Separating them with && does the trick but I noticed that semicolon delimitation worked as well. Here’s a line that will install VMware for you in one fell swoop:

sudo apt-get install linux-headers-$(uname -r) build-essential gcc-3.4 && tar xzf VMware-workstation-6.0.2-59824.i386.tar.gz && export CC=/usr/bin/gcc-3.4 && cd vmware-distrib && sudo ./vmware-install.pl

Another trick is to direct the output of one command into another like the following which subsets a process listing:

ps -aux | grep "wine"

It’s all good stuff and is the sort of thing that shows why so many Linux/UNIX types love their command line so much.

Here’s an idea that I got for a post before I spent that torrid weekend with Windows that caused me to jump ship to Linux. The idea of having a UNIX command line while still remaining in Windows did appeal to me at the time and Cygwin seems to provide an intriguing way to do this. At its most basic, it is a set of DLL’s that allow you to run standard UNIX commands in a shell like what you see below. However, it is extensible with a good number of packages that you can choose to install. NEdit is just one that gets included and I think that I spied Apache too. The standard installation is a web-based affair with your downloading only the components that you need; it’s worth trawling through the possibilities while you’re at it.

Now that I am firmly ensconced in the world of Linux, this may be one possibility that I will park, for a while anyway. After all, I now do have the full power of the UNIX command line…

The Windows 2000 command line feels an austere primitive when compared with the wonders of the UNIX/Linux equivalent. Windows XP feels a little better and PowerShell is another animal altogether. With the latter pair, you do get file or folder autocompletion upon hitting the TAB key. What I didn’t realise until recently was that continued tabbed cycled through the possibilities; I was hitting it once and retyping when I got the wrong folder or file. I stand corrected. With the shell in Linux/UNIX, you can get a listing of possibilities when you hit TAB for the second time and the first time only gives you completion as far as it can go with certainty; you’ll never get to the wrong place but you may not get anywhere at all. This works for bash but not ksh88 as far as I can see. It’s interesting how you can take two different approaches in order to reach the same end.

Mapping network drives in Windows usually involves shuffling through Explorer menus. There is another way that I consider to be neater: using the Windows command line ("DOS" to some). The basic command for creating a mapping goes like this:

net use w: \\yourserver.address

To ensure persistence of the mapping across different Windows sessions, use this:

net use w: \\yourserver.address /persistent:yes

Here’s how to set up a mapping that logs in as a different user:

net use w: \\yourserver.address password /user:you

The above can include domain information as well and in a number of different forms: domain\username is one.

To delete a mapping, try this:

net use w: /delete

List all existing mappings:

net use

This is a flavour of what is available and Microsoft does provide documentation. Issuing the following command will bring some of that on the command line:

net help use

One of the great features of the UNIX shell is that you can send the output from one command to another for further processing. Take the following example for instance:

ls -l | grep "Jul 12"

This takes the long directory file listing output and sends it to grep for subsetting (all files created today in this example) before it is returned to the screen. The | character is the pipe trigger and you can have as many pipes in your command as you want though readability may dictate how far you want to go.