Tag Archive for command

Sorting out MySQL on Arch Linux

November 5, 2011 No comments

Seeing Arch Linux running so solidly in a VirtualBox virtual box has me contemplating whether I should have it installed on a real PC. Saying that, recent announcements regarding the implementation of GNOME 3 in Linux Mint have caught my interest even if the idea of using a rolling distribution as my main home operating system still has a lot of appeal for me. Having an upheaval come my way every six months when a new version of Linux Mint is released is the main cause of that.

While remaining undecided, I continue to evaluate the idea of Arch Linux acting as my main OS for day-to-day home computing. Towards that end, I have set up a working web server instance on there using the usual combination of Apache, Perl, PHP and MySQL. Of these, it was MySQL that went the least smoothly of all because the daemon wouldn’t start for me.

It was then that I started to turn to Google for inspiration and a range of actions resulted that combined to give the result that I wanted. One problem was a lack of disk space caused by months of software upgrades. Since tools like it in other Linux distros allow you to clear some disk space of obsolete installation files, I decided to see if it was possible to do the same with pacman, the Arch Linux command line package manager. The following command, executed as root, cleared about 2 GB of cruft for me:

pacman -Sc

The S in the switch tells pacman to perform package database synchronization while the c instructs it to clear its cache of obsolete packages. In fact, using the following command as root every time an update is performed both updates software and removes redundant or outmoded packages:

pacman -Syuc

So I don’t forget the needful housekeeping, this will be what I use in future with the y being the switch for a refresh and the u triggering a system upgrade. It’s nice to have everything happen together without too much effort.

To do the required debugging that led me to the above along with other things, I issued the following command:

mysqld_safe –datadir=/var/lib/mysql/ &

This starts up the MySQL daemon in safe mode if all is working properly and it wasn’t in my case. Nevertheless, it creates a useful log file called myhost.err in /var/lib/mysql/. This gave me the messages that allowed the debugging of what was happening. It led me to installing net-tools and inettools using pacman; it was the latter of these that put hostname on my system and got the MySQL server startup a little further along. Other actions included unlocking the ibdata1 data file and removing the ib_logfile0 and ib_logfile1 files so as to gain something of a clean sheet. The kill command was used to shut down any lingering mysqld sessions too. To ensure that the ibdata1 file was unlocked, I executed the following commands:

mv ibdata1 ibdata1.bad
cp -a ibdata1.bad ibdata1

These renamed the original and then crated a new duplicate of it with the -a switch on the cp command forcing copying with greater integrity than normal. Along with the various file operations, I also created a link to my.cnf, the MySQL configuration file on Linux systems, in /etc using the following command executed by root:

ln -s /etc/mysql/ my.cnf /etc/my.cnf

While I am unsure if this made a real difference, uncommenting the lines in the same file that pertained to InnoDB tables. What directed me to these were complaints from mysqld_safe in the myhost.err log file. All I did was to uncomment the lines beginning with “innodb” and these were 116-118, 121-122 and 124-127 in my configuration file but it may be different in yours.

After all the above, the MySQL daemon ran happily and, more importantly, started when I rebooted the virtual machine. Thinking about it now, I believe that was a lack of disk space, the locking of a data file and the lack of InnoDB support that was stopping the MySQL service from running.Running commands like mysqld start weren’t yielding useful messages so a lot of digging was needed to get the result that I needed. In fact, that’s one of the reasons why I am sharing my experiences here.

In the end, creating databases and loading them with data was all that was needed for me to start see functioning websites on my (virtual) Arch Linux system. It turned out to be another step on the way to making it workable as a potential replacement for the Linux distributions that I use most often (Linux Mint, Fedora and Ubuntu).

Databases, Linux, Software, Virtualisation, Web Technologies, Web Tools

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TypeError: unable to create a wrapper for GLib.Variant

August 31, 2011 No comments

A little while ago, I wrote a piece on here telling of how I got GNOME 3 installed an working on Linux Mint. However, I have discovered since that there was an Achilles heel in the approach that I had taken: using the ricotz/testing PPA so that I could gain additional extensions for use with GNOME Shell. If this was just a repository of GNOME Shell extensions, that would be well and good but the maintainer(s) also has a more cutting edge of GNOME Shell in there too. Occasionally, updates from ricotz/testing have been the cause of introducing rough edges to my desktop environment that have resolved themselves within a few hours or days. However, updates came through in the last few days that broke GNOME Tweak Tool. When I tried running it from the command line, all I got was a load of output that included the message that heads this posting and no window popping up that I could use. That made me see sense so I stopped living dangerously by using that testing repository. Apparently, there is a staging variant too but a forum posting elsewhere on the web has warded me off from that too.

Until I encountered the latter posting, I had not heard of the ppa-purge tool and it came in handy for ridding my system of all packages from the ricotz repository and replacing with with alternatives from more stable ones such as that from the gnome3-team. This wasn’t installed on my computer so I added it in the usual fashion by issuing the following command:

sudo apt-get install ppa-purge

Once that was complete, I executes the following command with the ricotz/testing repository still active:

sudo ppa-purge testing ricotz

Once that was complete and everything was very nicely automated too, GNOME Tweak Tool was working again as intended and that’s the way that I intend keeping things. Another function of ppa-purge is that it has excised any mention of the ricotz/testing repos from my system too so nothing more can come from there.

While I was in the business of stabilising GNOME Shell on my system, I decided to add in UGR too. First, another repository needed to be added as follows:

sudo add-apt-repository ppa:ubuntugnometeam/ppa-gen
sudo apt-get update

The next steps were to install UGR once that was in place so these commands were issued to do the job:

sudo apt-get dist-upgrade
sudo apt-get install ugr-desktop-g3
sudo apt-get upgrade

While that had the less desirable effect of adding games that I didn’t need and have since removed, it otherwise worked well and I now have a new splash screen at starting up and shutting down times for my pains. Hopefully, it will main that any updates to GNOME Shell that come my way should be a little more polished too. All that’s needed now is for someone to set up a dedicated PPA for GNOME Shell Extensions so I could regain drop down menus in the top panel for things such as virtual desktops, places and other handy operations that perhaps should have been in GNOME Shell from the beginning. However, that’s another discussion so I’ll content myself with what I now have and see if my wish ever gets granted.

Linux, Software

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Setting up GNOME 3 on Arch Linux

July 22, 2011 8 comments

It must have been my curiosity that drove me to exploring Arch Linux a few weeks ago. Its coming on a Linux Format DVD and a few kind words about its being a cutting edge distribution were enough to set me installing it into a VirtualBox virtual machine for a spot of investigation. In spite of warnings to the contrary, I took the path of least resistance with the installation even though I did look among the packages to see if I could select a desktop environment to be added as well. Not finding anything like GNOME in there, I left everything as defaulted and ended up with a command line interface as I suspected. The next job was to use the pacman command to add the extras that were needed to set in place a fully functioning desktop.

For this, the Arch Linux wiki is a copious source of information though it didn’t stop me doing things out of sequence. That I didn’t go about perusing it in a linear manner was part of the cause of this but you have to know which place to start first as well. As a result, I have decided to draw everything together here so that it’s all in one place and in a more sensible order even if it wasn’t the one that I followed.

The first thing to do is go adding X.org using the following command:

pacman -Syu xorg-server

The -Syu switch tells pacman to update the package list, upgrade any packages that require it and add the listed package if it isn’t in place already; that’s X.org in this case. For my testing, I added xor-xinit too. This puts that startx command in place. This is the command for adding it:

pacman -S xorg-xinit

With those in place, I’d go adding the VirtualBox Guest Additions next. GNOME Shell requires 3D capability so you need to have this done while the machine is off or when setting it up in the first place. This command will add the required VirtualBox extensions:

pacman -Syu virtualbox-guest-additions

Once that’s done, you need to edit /etc/rc.conf by adding “vboxguest vboxsf vboxvideo” within the brackets on the MODULES line and adding “rc.vboxadd” within the brackets on the DAEMONS line. On restarting everything should be available to you but the modprobe command is there for any troubleshooting.

With the above pre-work done, you can set to installing GNOME and I added the basic desktop from the gnome package and the other GNOME applications from the gnome-extra one. GDM is the login screen manager so that’s needed too and the GNOME Tweak Tool is a very handy thing to have for changing settings that you otherwise couldn’t. Here are the commands that I used to add all of these:

pacman -Syu gnome
pacman -Syu gnome-extra
pacman -Syu gdm
pacman -Syu gnome-tweak-tool

With those in place, some configuration files were edited so that a GUI was on show instead of a black screen with a command prompt, as useful as that can be. The first of these was /etc/rc.conf where “dbus” was added within the brackets on the DAEMONS line and “fuse” was added between those on the MODULES one.

Creating a file named .xinitrc in the root home area with the following line in there makes running a GNOME session from issuing a startx command:

exec ck-launch-session gnome-session

With all those in place, all that was needed to get a GNOME 3 login screen was a reboot. Arch is so pared back that I could login as root, not the safest of things to be doing so I added an account for more regular use. After that, it has been a matter of tweaking the GNOME desktop environment and adding missing applications. The bare bones installation that I allowed to happen meant that there were a surprising number of them but that isn’t hard to fix using pacman.

All of this emphasises that Arch Linux is for those who want to pick what they want from an operating system rather than having that decided for you by someone else, an approach that has something going for it with some of the decisions that make their presence felt in computing environments from time to time. There’s no doubt that this isn’t for everyone but documentation is complete enough for the minimalism not to be a problem for experienced Linux users and I certainly managed to make things work for me once I got them in the right order. Another thing in its favour is that Arch also is a rolling distribution so you don’t need have to go though the whole set up routine every six months unlike some others. So far, it does seem stable enough and even has set me to wondering if I could pop it on a real computer sometime.

Linux, Software

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On Upgrading to Linux Mint 11

May 31, 2011 One comment

For a Linux distribution that focuses on user friendliness, it does surprise me that Linux Mint offers no seamless upgrade path. In fact, the underlying philosophy is that upgrading an operating system is a risky business. However, I have been doing in-situ upgrades for both Ubuntu and Fedora for a few years without any real calamities. A mishap with a hard drive that resulted in lost data in the days when I mainly was a Windows user places this into sharp relief. These days, I am far more careful but thought nothing of sticking a Fedora DVD into a drive to move my Fedora machine from 14 to 15 recently. Apart from a few rough edges and the need to get used to GNOME 3 together with making a better fit for me, there was no problem to report. The same sort of outcome used to apply to those online Ubuntu upgrades that I was accustomed to doing.

The recommended approach for Linux Mint is to backup your package lists and your data before the upgrade. Doing the former is a boon because it automates adding the extras that a standard CD or DVD installation doesn’t do. While I did do a little backing up of data, it wasn’t total because I know how to identify my drives and take my time over things. Apache settings and the contents of MySQL databases were my main concern because of where these are stored.

When I was ready to do so, I popped a DVD in the drive and carried out a fresh installation into the partition where my operating system files are kept. Being a Live DVD, I was able to set up any drive and partition mappings with reference to Mint’s Disk Utility. What didn’t go so well was the GRUB installation and it was due to the choice that I made in one of the installation screens. Despite doing an installation of version 10 just over a month ago, I had overlooked an intricacy of the task and placed GRUB on the operating system files partition rather than at the top level for the disk where it is located. Instead of trying to address this manually, I took the easier and more time-consuming step of repeating the installation like I did the last time. If there was a graphical tool for addressing GRUB problems, I might have gone for that instead but am left wondering at why there isn’t one included at all. Maybe it’s something that the people behind GRUB should consider creating unless there is one out there already about which I know nothing.

With the booting problem sorted, I tried logging in only to find a problem with my desktop that made the system next to unusable. It was back to the DVD and I moved many of the configuration files and folders (the ones with names beginning with a “.”) from my home directory in the belief that there might have been an incompatibility. That action gained me a fully usable desktop environment but I now think that the cause of my problem may have been different to what I initially suspected. Later I discovered that ownership of files in my home area elsewhere wasn’t associated with my user ID though there was no change to it during the installation. As it happened, few minutes with the chown command were enough to sort out the permissions issue.

The restoration of the extra software that I had added beyond what standardly gets installed was took its share of time but the use of a previously prepared list made things so much easier. That it didn’t work smoothly because some packages couldn’t be found the first time around so another one was needed. Nevertheless, that is nothing compared to the effort needed to do the same thing by issuing an installation command at a time. Once the usual distribution software updates were in place, all that was left was to update VirtualBox to the latest version, install a Citrix client and add a PHP plugin to NetBeans. Then, next to everything was in place for me.

Next, Apache settings were restored as were the databases that I used for offline web development. That nearly was all that was needed to get offline websites working but for the need to add an alias for localhost.localdomain. That required installation of the Network Settings tool so that I could add the alias in its Hosts tab. With that out of the way, the system had been settled in and was ready for real work.

In light of some of the glitches that I saw, I can understand the level of caution regarding a more automated upgrade process on the part of the Linux Mint team. Even so, I still am wondering if the more manual alternative that they have pursued brings its own problems in the form of those that I met. The fact that the whole process took a few hours in comparison to the hour taken by the in-situ upgrades that I mentioned earlier is another consideration that makes you wonder if it is all worth it every six months or so. Saying that, there is something to letting a user decide when to upgrade rather than luring one along to a new version, a point that is more than pertinent in light of the recent changes made to Ubuntu and Fedora. Whichever approach you care to choose, there are arguments in favour as well as counterarguments too.

Linux, Software

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GNOME 3 in Fedora 15: A Case of Acclimatisation and Configuration

May 29, 2011 8 comments

When I gave the beta version of the now finally released Fedora 15 a try, GNOME 3 left me thinking that it was even more dramatic and less desirable a change than Ubuntu’s Unity desktop interface. In fact, I was left with serious questions about its actual usability, even for someone like me. It all felt as if everything was one click further away from me and thoughts of what this could mean for anyone seriously afflicted by RSI started to surface in my mind, especially with big screens like my 24″ Iiyama being commonplace these days. Another missing item was somewhere on the desktop interface for shutting down or restarting a PC; it seemed to be case of first logging off and then shutting down from the login screen. This was yet another case of adding to the number of steps for doing something between GNOME 2 and GNOME 3 with its GNOME Shell.

After that less than positive experience with a Live CD, you’d be forgiven for thinking that I’d be giving the GNOME edition of Fedora 15 a wide berth with the LXDE one being chosen in its place. Another alternative approach would have been to turn off GNOME Shell altogether by forcing the fallback mode to run all the time. The way to do this is start up the System Settings application and click on the System Info icon. Once in there, click on Graphics and turn on the Forced Fallback Mode option. With that done, closing down the application, logging off and then back on again will gain you an environment not dissimilar to the GNOME 2 of Fedora 14 and its forbears.

Even after considering the above easy way to get away from and maybe even avoid the world of GNOME Shell, I still decided to give it another go to see if I could make it work in a way that was less alien to me. After looking at the handy quickstart guide, I ventured into the world of GNOME Shell extensions and very useful these have come to be too. The first of these that I added was the Alternate Status Menu and I ran the following command to do so:

yum install gnome-shell-extensions-alternative-status-menu

The result was that the “me” menu gained the ever useful “Power Off…” entry that I was seeking once I refreshed the desktop by running the command r in the command entry box produced by the ALT + F2 keyboard combination. Next up was the Place Menu and the command used to add that is:

yum install gnome-shell-extensions-place-menu

Again, refreshing the desktop as described for the Alternate Status Menu added the new menu to the (top) panel. Not having an application dock on screen all the time was the next irritation that was obliterated and it helps to get around the lack of a workspace switcher for now too. The GNOME Shell approach to virtual desktops is to have a dynamic number of workspaces with there always being one more than what you are using. It’s an interesting way of working that doesn’t perturb more pragmatic users like me but there are those accustomed to tying applications to particular workspaces aren’t so impressed by the change. The other change to workspace handling is that keyboard shortcuts have changed to CTRL-ALT-[Up Arrow] and CTRL-ALT-[Down Arrow] from CTRL-ALT-[Left Arrow] and CTRL-ALT-[Right Arrow].

To add that application dock, I issued the command below and refreshed the desktop to get it showing. Though it stops application windows becoming fully maximised on the screen, that’s not a problem with my widescreen monitor. In fact, it even helps to switch between workspaces using the keyboard because that doesn’t seem to be working when you have fully maximised windows.

yum install gnome-shell-extensions-dock

After adding the application dock, I stopped adding extensions though there are more available such as Alternate Tab Behaviour (restores the ALT-TAB behaviour of GNOME 2), Auto Move Windows, Drive Menu, Native Window Placement, Theme Selector and Window Navigator. Here are the YUM commands for each of these in turn:

yum install gnome-shell-extensions-alternate-tab
yum install gnome-shell-extensions-auto-move-windows
yum install gnome-shell-extensions-drive-menu
yum install gnome-shell-extensions-native-window-placement
yum install gnome-shell-extensions-theme-selector
yum install gnome-shell-extensions-user-theme
yum install gnome-shell-extensions-windowsNavigator

One hope that I will retain is that more of these extensions will appear over time but Ranjith Siji seems to have a good round up of what is available. Other than these, I also have added the DCONF Editor and GNOME Tweaks Tool with the latter restoring buttons for minimising and maximising windows to their title bars for me. As ever, YUM was called to add them using the following commands:

yum install dconf-editor
yum install gnome-tweaks-tool

There are other things that can be done with these but I haven’t to explore them yet. All YUM commands were run as root and the ones that I used certainly have helped me to make myself at home in what once was a very unfamiliar desktop environment for me. In fact, I am beginning to like what has be done with GNOME 3 though I have doubts as to how attractive it would be to a user coming to Linux from the world of Windows. While everything is solidly crafted, the fact that I needed to make some customisations of my own raises questions about how suitable the default GNOME set-up in Fedora is for a new user though Fedora probably isn’t intended for that user group anyway. Things get more interesting when you consider distros favouring new and less technical users, both of whom need to be served anyway.

Ubuntu has gone its own way with Unity and, having spent time with GNOME 3, I can see why they might have done that. Unity does put a lot more near at hand on the desktop than is the case with GNOME 3 where you find yourself going to the Activities window a lot, either by using your mouse or by keystrokes like the “super” (or Windows) key or ALT-F1. Even so, there are common touches like searching for an application like you would search a web page in Firefox. In retrospect, it is a pity to see the divergence when something from both camps might have helped for a better user experience. Nevertheless, I am reaching the conclusion that the Unity approach feels like a compromise and that GNOME feels that little bit more polished. Saying that, an extra extension or two put more items nearer to hand in GNOME Shell would be desirable. If I hadn’t found a haven like Linux Mint where big interface changes are going to be avoided, maybe going with the new GNOME desktop mightn’t have been a bad thing to do after all.

Linux, Software

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Restoring GRUB for Ubuntu 10.10

November 27, 2010 No comments

Once you end up with Windows overwriting your master boot record (MBR), you have lost the ability to use GRUB. Therefore, it would be handy to get it back if you want to start up Linux again. Though the loss of GRUB from the MBR was a deliberate act of mine, I knew that I’d have to restore GRUB to get Linux working again.Therefore, I addressed the situation with an Ubuntu 10.10 Live DVD. Once that had loaded its copy of the distribution, I issued the following command to get things back again:

sudo grub-install –root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda

When there were error messages, I tried this one to see if I could get more information:

sudo grub-install –root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda –recheck

In the end, any messages that I was getting didn’t seem to be critical and GRUB worked without a hitch. The next stage was to add an entry for Windows 7 to the GRUB menu and, with that instated, I was able to dual-boot Ubuntu and Windows using GRUB to select which one was to start for me.

Linux, Software

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