Adventures & experiences in contemporary technology
One thing that is very handy for shell scripting is to have automated entry of passwords for logging into other servers. This can involve using plain text files, which is not always ideal so it was good to find an alternative. The first step is to use the keygen tool that comes with SSH. The command is given below and the -t switch specifies the type of key to be made, RSA in this case. There is the option to add a passphrase but I decided against this for sake of convenience and you do need to assess your security needs before embarking on such a course of action.
ssh-keygen -t rsa
The next step is to use the ssh-copy-id command to generate the keys for a set of login credentials. For this, it is better to use a user account with restricted access to keep as much server security as you can. Otherwise, the process is as simple as executing a command like the following and entering the password at the prompt for doing so.
ssh-copy-id [user ID]@[server address]
Getting this set up has been useful for running a file upload script to keep a web server synchronised and it is better to have the credentials encrypted rather than kept in a plain text file.
Recently, I tried using Commento with a static website that I was developing and this needed PostgreSQL rather than MySQL or MariaDB, which many content management tools use. That meant a learning curve that made me buy a book as well as the creation of a system account for administering PostgreSQL. These are not the kind of things that you want to be too visible so I wanted to hide them.
Since Linux Mint uses AccountsService, you cannot use lightdm to do this (the comments in /etc/lightdm/users.conf suggest as much). Instead, you need to go to /var/lib/AccountsService/users and look for a file called after the user name. If one exists, all that is needed is for you to add the following line under the [User] section:
SystemAccount=true
If there is no file present for the user in question, then you need to create one with the following lines in there:
[User]
SystemAccount=true
Once the configuration files are set up as needed, AccountsService needs to be restarted and the following command does that deed:
sudo systemctl restart accounts-daemon.service
Logging out should reveal that the user in question is not listed on the logon screen as required.
During the week, I did an update on my Sabayon system and GNOME 3.6 came on board without to much of a bother. There was no system meltdown or need for an operating system re-installation. However, there was one matter that rankled: adding and updating extensions from extensions. gnome.org was impossible. The process would create a new folder in ~/.local/share/gnome-shell/extensions/ but not fill it with anything at all. Populating from another my Ubuntu GNOME Remix 12.10 machine didn’t seem to achieve the needful and I am left wondering if it is down to the version of GNOME Shell being 3.6.2. However, even adding an entry for the current version of GNOME Shell to metadata.json for one plugin didn’t appear to do what I wanted so resolving this issue needs further enquiry.
In the meantime, I added the Cinnamon desktop environment using the following command and will be using that from now on. If the GNOME Shell extension issue ever gets sorted I may move back but there is no rush. GNOME 3.8 sounds like it’s bringing an interesting option that makes use of the approach Linux Mint took for version 12 of that distribution and I can await that, especially if it avoids the need for adding extension on a personal basis like now.
sudo equo update && sudo equo install cinnamon
With the installation completed by the above command, it was a matter of logging out and choosing the Cinnamon entry (there is a 2D version too) from the session dropdown menu on the login screen to get it going. Then, it was a matter of tweaking Cinnamon to my heart’s content. Getting a two panel layout required logging out and in again as well as choosing the appropriate setting in the Cinnamon Panel options tab. Next, I decided to check on what themes are available at cinnamon.linuxmint.org before settling on Cinnamint 1.6. It all feels very comfortable apart from not having an automatically growing list of workspaces that are a default offering in GNOME Shell. That goes against the design principles of Cinnamon though so only hopes of someone making an extension that does that are left.
Another feature of Ubuntu 11.10 and Linux Mint 12 is the appearance of a Guest Account entry on their login screens. Windows has had this feature for a while now but it is easy to turn it off if you know where to look. Somehow, Ubuntu and Linux Mint haven’t made it obvious as it could be. In both cases, you have to edit /etc/lightdm/lightdm.conf and add the following line to the bottom of the file:
allow-guest=false
That removes the entry in question and could a little more security. In Ubuntu, there are lines in the file controlling the background image that you have for your login screen. In my experience, Linux Mint stores this in the greeter file referenced in lightdm.conf and that’s unity-greeter in my case though I mostly use GNOME 3 with only the occasional stint using the MATE desktop environment.
Here’s a useful idea: get your blog login page to look like it’s part of your blog. It does work well on my hillwalking blog but you do have to watch how it behaves with whatever theme you are using. Strangely, I couldn’t get it to work on my offline blog, the development mirror of what you see online. The ability to set what page is displayed after logging in or logging out is an especially useful inclusion.
These sound like really good ideas: being able to control the running order of things on your blog sidebar is a good thing. What scuppered my using them is that you need widgets turned on for the effect to work and i have seen issues with how ID’s have been set when things are widgetised.