Monthly Archives: December 2012

Users on Linux

Quick notes on adding users in Linux. As they say,, check the man pages or get a good book on the subject for more detail. One such book, The Linux Cookbook by Carla Schroder, published by OReilly Press.

Adding new user.

To add a new user and have the system automatically generate them a home directory. Example for Sarah.
useradd -m Sarah

To include space for the GECOS data, use the comment option -c. Typically there are 5
fields. If you just want their full name listed, leave the other fields blank by adding
commas:
useradd -m m -c Sarah Johnson,,,, Sarah

Note, her login name will just be Sarah. This must be unique on the system. Once you’ve run this command, you need to set her password with:

passwd Sarah

You’re then prompted to enter and confirm the new password. There are other options with passwd. For example, -e, expire password at first login, forcing the user to choose a new one. –x specify how long the password will be valid for, in days. -w. Specify how many days before expiry the user should get a warning.

Preventing a user having shell access.

For example, if they have an account on the system just to retrieve email with a client. You need to indicate their shell access is:
/bin/nologin

As opposed to.
/bin/bash

or whatever shell you’re generally using.

You can use the usermod command to set this if the user already exists. Example, no shell access for Derek:
usermod -s /bin/nologin derek

If you’re adding a new user called jerry:
useradd -s /bin/nologin jerry

You can also directly edit passwd instead if you really want, however, it’s a good idea to back up files such as that before manually editing. For example.
cp /etc/passwd b/etc/bk.passwd

To suspend a users account, let’s call them Dan, probably the best way is to use:
passwd -l Dan

To rre-enable their account:
# passwd -u Dan

Again, this can also be done by manually editting the passwd file. I.e. putting an “!” mark at the beginning of the password field or replacing the “x” with an “*”.

An intro to Vinux

Vinux is an accessible Linux distribution put together by the very helpful people behind the Vinux Project.
Vinuxproject.org

Vinux can be run as a live boot version from CD, DVD or USB memory stick. The current version of Vinux is based off the Ubuntu Lucid Linx LTS version, 10.4. The current Vinux version at time of writing is 3.2. Check the Vinux project website for more detail and links to downloads. One of the great things about this distro, aside it being produced with low vision or blind users in mind and tweaked accordingly, is that it will talk you through it’s very installation. With out setting scripts for an unattended installation, to my knowledge there’s simply no way a blind computer user can install Windows independently. Microsoft’s very basic screen reader, Narrator, doesn’t run from the installation media, so you’re reliant on sighted help. Being able to setup Vinux from the get go, is a real bonus in my opinion.

The hardware I’m currently running it on is a 6 year old Dell laptop, with 512MB RAM, 1.7 Pentium Mobile processor. By these day’s standards a puny machine. In fact, it was becoming barely useable under Windows XP and needed a fresh reinstallation. (Something frankly I couldn’t be bothered to do, even if I’d found the Dell recovery disk.) SO having tested Vinux from a USB live version and become quite impressed, I decided to install.

At that time, I did this as a side by side installation with Windows. This presents the user with a Grub bootloader menu. This is not spoken of course as no operating system has loaded yet. Therefor it’s a good idea to get someone to read you the menu order and memorise the options.

Whilst I found running the USB live version pretty reliable, having installed to HD, I had various problems with losing speech and inconsistency with whether speech would start at all after boot. The screen reader itself Orca was loaded but no speech. With out going into describing the minimally successful adjustments, made after Googling the issue, eventually I waited until the new 3.2 version of Vinux was released earlier this year (2012.) Since then the system has been far more useable, reliable and productive.

As blind computer or technology users in general, there are always little nagging unforeseen (no pun intended) problems. Some things are resolved and improved as a technology matures. Conversely, new software can break previous access methodologies. Not exclusive issues to users of access technology of course. With that in mind, what the volunteers in the Vinux Project have done is invaluable in furthering the accessibility of computing to blind and visually impaired users.

Whilst I can’t replace Windows with Vinux at this time. (There’s simply too much software I need on that oS.) Linux and this particular distro, for it’s working straight out the box, are my go to system as I learn more about networking and system admin. Of course a great many people are now using Linux systems for more general applications, web surfing, document processing and so on. People previously tied to the Microsoft world have been increasingly enticed by distros such as Ubuntu and Mint. Blind people too have been using Linux in various ways for several years. Orca, the screen reader on the Gnome desktop environment has been around a while. However, getting it all working involved having to learn to make a considerable amount of technical tweaks and problem solving. Not something any average computer user wants to do. So for a newbie like myself, Vinux whilst by no means perfect, has really moved things on and I thank all those involved in the ongoing project for bringing this advancement.

To try Vinux out, I’d recommend booting it live off a USB stick. If in the seemingly unlikely event, your BIOS doesn’t support that but you have a reasonably powerful machine, you can run it in a virtual machine. Instructions for both can be found by going to.
Vinuxproject.org

NB: The link to the Virtual Edition from the front page is broken. Go to the downloads section.