Linux Tips

OpenSuSe 11.4

2011-10-27T20:58:00.002+05:30

Gnome Shell 3 on OpenSuSE with Nord Shell theme and Sonar GTK theme

After having installed Xubuntu 11.10 over my install of Ubuntu 11.04, and even though it was working perfectly, I committed the mistake of installing Unity Desktop. I further aggravated the scene by installing Gnome Shell as well. I liked neither the Unity Desktop nor the Gnome Shell basically as I found it difficult to customize it as much as I would have liked to, even using Gnome-Tweak-Tool.

Then I downloaded OpenSuSE 11.4 (KDE) and installed it. Though it was very polished, I found that some times the user interface lagged. Having been used to the smoothly functioning interface of Ubuntu, I started hating it eventually. Then I tried installing Gnome 3 and liked it instantly.

Then yesterday, I felt like upgrading to Gnome 3.2 and downloaded the live iso from the www.gnome.org. After installing it, I found that there were some rough edges to Gnome 3.2. So, I downloaded OpenSuSE 11.4 Gnome version and installed it and found it perfect for my requirements. Now I am off Ubuntu for sometime atleast.

Ubuntu 10.10 Maverick Meerkat - A Pleasant Experience

2010-12-18T21:39:00.004+05:30

Finally, 2 months after the release of Maverick Meerkat, I ventured to install it on my laptop. After using it for the past two days, I found it to be extremely user friendly. The User Interface is very elegant. Hardware detection is

excellent. All the much-hyped features are no exaggeration. They make the user experience a very pleasant one. However, there still are certain rough edges that mar the overall effect. Nothing serious though!

My first gripe is that I am unable to add Facebook to gwibber, the new social networking app. It seems to be a well-documented and hitherto unresolved bug. It doesn't matter much really, but I wish this bug would disappear so that the experience would become more pleasant.

The next irritant is a more serious one. The synaptics bug relating to two-touch gesture issue still persists and calls for an ugly work around! It still requires a script involving xinput to be executed each time I log in to make multi-touch work with synaptics. Ok, but the greater problem is, that I have to execute the script each time I log in, resume from suspend or resume from hibernation, which I often do. I wish something is done in this regards as well.

Besides these two irritants the others are minor and can be easily ignored. Overall I am having a nice time using Ubuntu 10.10.

To Make A Self-Reading Text File!

2010-11-12T18:23:00.002+05:30

To make a text file self-read, add the following line at the beginning of the file -
#!/bin/more
then make the file executable -
$ chmod +x
The file can be executed as
$ ./filename.txt

Finding the type of a file!

2010-07-07T18:53:00.003+05:30

Sometimes it so happens that you want to determine the type of a particular file. I found the following command useful when I was converting the format of certain audio files.

$ file somefile.xyz

This outputs the type of the file somefile.xyz

Unmount a busy external drive!

2010-06-20T17:17:00.002+05:30

It so happens that sometimes when you try to umount your pendrive, the system reports -

umount: /media/xyz : device is busy

It is clear that some process is using the drive. It would be nice to quickly find out the errant process so that necessary action can be taken.

We can find out which process is using the drive by fuser command -

#fuser -m /dev/sdx

where /dev/sdx is mounted on /media/xyz

Let us say that the output of the above command is

/dev/sdx: 538

Then

#ps -aux|grep 538

reveals the name of the errant programme, in my case rhythmbox :-)

To change the GDM login background in Ubuntu Karmic Koala

2010-05-11T19:23:00.003+05:30

I found to my utter consternation that one cannot change the login background in Ubuntu Karmic Koala (or Linux Mint 8, for that matter) from gdmsetup.

I found this solution after a bit of googling -
Firstly, we log out of the current session and return to the GDM login screen.
At this point, pressing Ctrl-Alt-F1 throws up the terminal.
Login to this terminal with your username and password.
Then issue the following command -
$export DISPLAY=:0.0
followed by -
$sudo -u gdm gnome-control-center.
At this point, pressing Alt-F7 brings us back to the GDM login screen with gnome-control-center
Selecting Appearance from gnome-control-center and making the appropriate changes to the background, font.
Closing the gnome-control-center window reveals the login screen with the new background.

Changing the default display manager (GDM / KDM / XDM etc.) in Slackware

2009-08-14T12:07:00.001+05:30

To change the Display Manager in Slackware, we have to edit the /etc/rc.d/rc.4 file as root user.

extracting audio from video (.flv) files downloaded from Youtube - the Linux way!

2009-08-10T14:22:00.004+05:30

I had downloaded some videos from Youtube and wanted to extract the soundtrack as an .mp3 file or .ogg file.
At first I tried the following command -
$ mplayer -dumpaudio my_file.flv -dumpfile my_file.mp3
Most of the times the audio was extracted perfectly. But some .flv files proved stubborn, and I was left with non-playable mp3s.
I found a solution at LinuxQuestions.org, where a knowledgeable member Ilgar provided the following solution
$ mplayer -quiet my_file.flv -ao pcm:fast:file=my_file.mp3 -vc dummy -vo null -channels 2
after which I was left with my_file.mp3 .
$ file my_file.mp3
revealed that it was a WAV file and not an mp3. It was still playable with mplayer. However when I downloaded it on my Samsung UltraTouch S8300 mobile, I was not able to play it.
I then converted it to .mp3 format using the app - SoundConverter.
Thanks Ilgar

Scim error with OpenOffice 3.1

2009-07-28T17:13:00.003+05:30

I was getting the following error when I pressed Ctrl + Space in OpenOffice window to initiate scim -

Gtk-WARNING **: /opt/openoffice.org3/program/../basis-link/ure-link/lib/libstdc++.so.6: version `GLIBCXX_3.4.9' not found (required by /usr/lib/gtk-2.0/immodules/im-scim.so)

After a bit of googling I found a solution -

cd /opt/openoffice.org3/basis-link/ure-link/lib

sudo mv libstdc++.so.6 libstdc++.so.6.orig
sudo ln -s /usr/lib/libstdc++.so.6.0.9 libstdc++.so.6

sudo mv libgcc_s.so.1 libgcc_s.so.1.orig
sudo ln -s /usr/lib/libgcc_s.so.1 libgcc_s.so.1

Got touchpad to scroll

2009-06-14T09:44:00.003+05:30

After upgrading to Slackware 12.2, the touchpad on my laptop was not scrolling. After a bit of googling, I found this thread -
http://www.linuxquestions.org/questions/slackware-14/synaptics-touchpad-in-slackware-12.2-on-hp-g60-702809/#post3573157

as suggested in the above link, I changed the line

options psmouse proto=imps

options psmouse proto=auto

in /etc/modprobe.d/psmouse

then after reloading the psmouse module, and restarting X, my touchpad was scrolling.

Getting Right Alt key to work

2009-04-09T10:16:00.003+05:30

The right alt key press was eliciting no response on my Ubuntu 8.10 laptop in Gnome. After a bit of Googling, I found the following solution -
System -> Preferences -> Keyboard
Here choose Layouts tab. Then choose Other Options button. Keyboard Layout Options widow pops up. In this click on Alt/Win key behaviour and select -
Alt and Meta are on Alt keys.
This should solve the problem.

How I set right non-functional spell-checker in OpenOffice.org3

2008-12-12T17:52:00.004+05:30

Spell Checker was not working in my install of OpenOffice.org3 on Slackware 12.1. Wrongly spelt words were not being highlighted. Pressing F7 after selecting text containing spelling-errors was not detecting any errors. After a lot of skulduggery and quite a bit of googling, I realized that the problem was some how related to locales, hence I added the following line to /opt/openoffice.org3/program/soffice -

export LANG=en_US

Now spell checker works!

Empty Applications Menu? Repopulate it.

2008-08-31T08:44:00.002+05:30

All of a sudden, one fine morning I found that the Applications Menu in GNOME on my Ubuntu 8.04 laptop was empty. When I clicked on the Applications Menu, all I got was a small rectangular box, about a few pixels in dimensions. I found a solution to this, (the solution was the first result that Google threw at me). This problem seems to occur when there is not much hard disk space left. When this occurs, you are unable to run alacarte even from command prompt.
The solution is to delete the applications.menu file from ~/.config/menus/ directory.
$rm ~/.config/menus/applications.menu
After this the Applications Menu is restored.

ls tips - 1

2008-08-23T09:52:00.002+05:30

Sometimes it becomes necessary to search for all files that end in a particular character, like, for example a digit. The following command will list out all files that have filenames ending in a digit -

$ ls | grep '[0-9]$'

It is essential that the $ symbol is placed after the paranthesis. This $ symbol will cause grep to look for the digits from 0 to 9 at the end of the filename.
A better way would be -

$ ls | grep '[[:digit:]]$'

Similarly, if you want to search for filenames that begin with a digit, here is the command -

$ ls | grep '^[0-9]'

$ ls | grep '^[[:digit:]]'

This will list all filenames that begin with a character.

Giving Maximum processing time to any process

2008-08-22T17:49:00.003+05:30

To give maximum processing time to any process, first the PID of the process has to be determined using the command ps. Say you have firefox running and you want to determine its PID.

$ ps -A | grep firefox

on my system gives the following output

12845 pts/0 00:04:00 firefox

so 12845 is the required PID.
By issuing the following command we can give maximum priority (-20) to the particular process -

$ sudo renice -20 12845

This can be ascertained using the 'top' command.

Re-installing GRUB in Ubuntu

2008-08-22T17:32:00.002+05:30

Imagine a scenario, wherein you have installed a brand new distro on a system that already has some other distro installed. You have properly configured the GRUB to enable you to multi-boot. Now for some reason, you do not like the GRUB of the distro that was last to be installed, you want to revert back to the previous one. So what do we do now?
The solution is to boot into the required distro from the GRUB menu and then follow these steps -
1. Login as root from the command prompt and enter the following command
# sudo grub
grub > find /boot/grub/stage1

Let us say, the command returns (hdx,y).
2. Then enter the following commands -
grub > root(hdx,y)
grub > setup (hdx)
grub > quit

That's it! When you reboot, you'll be presented with the previous GRUB screen.

Getting the Touchpad to work in Slackware!

2008-07-31T12:10:00.002+05:30

This is how I got the touchpad on my laptop to work using synaptics.

After installing synaptics, the following lines have to be added to /etc/X11/xorg.conf. Before fiddling with xorg.conf, it is always suggested that you take a backup of the file -

# cp /etc/X11/xorg.conf /etc/X11/xorg.conf.old

The lines to be added to xorg.conf are as follows -

Section "Module"
Load "synaptics
EndSection

Then in the "InputDevice" Section -

Section "InputDevice"

Identifier "Synaptics Mouse"
Driver "synaptics"
Option "Device" "/dev/psaux"
Option "Protocol" "auto-dev"
Option "HorizEdgeScroll" "0"
Option "LeftEdge" "1700"
Option "RightEdge" "5300"
Option "TopEdge" "1700"
Option "BottomEdge" "4200"
Option "FingerLow" "25"
Option "FingerHigh" "30"
Option "MaxTapTime" "180"
Option "MaxTapMove" "220"
Option "VertScrollDelta" "100"
Option "HorizScrollDelta" "100"
Option "MinSpeed" "0.09"
Option "MaxSpeed" "0.18"
Option "AccelFactor" "0.0015"
Option "SHMConfig" "on"
Option "TapButton1" "1"
Option "TapButton2" "2"
Option "TapButton3" "3"

EndSection

Then in the "ServerLayout" Section

Section "ServerLayout"

Input Device "Synaptics Mouse" "CorePointer"

EndSection

After this reload the "psmouse" module as follows -

$ sudo modprobe -r psmouse
$ sudo modprobe psmouse

This should be added to your startup scripts.
The touchpad should be working after you reboot.

Command Line Music Player!

2008-07-20T22:19:00.002+05:30

mpg321 can be used to play mp3 files from command line. We can even create a playlist of all the songs stored in various directories and play the list via mpg321. If your songs are stored in various folders, the folder names can be appended to the file-names using the following script. First of all the spaces have to be removed from the file names (as described in a previous post). Then we can create the following script -

#!/bin/bash
for i in *;
do
a=$i;
b=`echo $PWD\`$i;
echo $b >> playlist; # the file names are stored in "playlist"
done

this way the names of all the files in all the subdirectories will be stored in "playlist" along with the appropriate path. Then we can play the list
as follows -

$ mpg321 --list playlist -z # -z for shuffle mode

That is it! Enjoy your music! Here we are assuming that all files are stored in various subdirectories of one parent directory, say 'music'. The script has to executed from the directory 'music'.

Samsung ML 2010 on Slackware 12.1

2008-07-20T11:15:00.003+05:30

The Samsung ML 2010 is automatically configured on Ubuntu, however on Slackware 12.1, the Samsung Unified Driver fails to install with the following error -

Unable to restart cups, script not found.

After going through the install script install.sh in the cdroot/Linux directory created by untarring the driver, if found that the para - restart-cups() in the install.sh script reads as follows -

.....
elif test -e /etc/init.d/cupsys; then
CUPS_SCRIPT=/etc/init.d/cupsys
.....

it is obvious that the installer wouldn't work. So I changed it to

.....
elif test -e /etc/rc.d/rc.cups; then
CUPS_SCRIPT=/etc/rc.d/rc.cups
.....

Moreover, the driver to be used for this printer is the one for 2150 and not 2010, that is the right driver is ML-2150 SPL II instead of ML-2010.

Removing spaces from file names!

2008-07-19T23:27:00.003+05:30

The following script, which I found here after an hour of googling, can be used to remove spaces and replacing them with any character (like '_') from file names

$ for f in *; do
> file=$(echo $f | tr ' ' _)
> [ ! -f $file ] && mv "$f" $file
> done
$

Command line utility to print a Calendar

2008-07-19T20:58:00.002+05:30

$ cal

will print out a calendar for the current month on the screen.

$ cal 2008

will do the same for the year 2008.

$ cal 03 2008

will do the same for the month of March, 2008. If, however, we want to print the calendar as a .ps file, we can use the pcal utility.

$ pcal -w 2008 -s 0:0:0 -P a4 > 2008.ps

We can convert this .ps file to .pdf using

$ ps2pdf 2008.ps 2008.pdf

Command Line Calculator!

2008-07-19T19:48:00.002+05:30

To do small calculations without starting your calculator utility here is a small trick. Suppose you want to multiply 2 and 3, do this -

$ echo $[2*3]

However if you wanted to divide 2 by 3

$ echo $[2/3]

would give a '0'.

We can still make use of the command line to get the correct answer. We have to use 'bc'. Like this -

$ echo '2 / 3' | bc -l

Here is the output -

.66666666666666666666

Magic Keys (Alt + SysRq)

2008-07-18T19:19:00.003+05:30

When your Linux install completely refuses to respond and no amount of coaxing and cajoling brings it back to life you can try -
Alt + SysRq + k
This will kill all running programmes and will drop you back to the login screen.

Even this fails? The try this -

Alt + SysRq + r + e + i + s + u + b
This is easy to remember with the help of the mnemonic "Raising Elephants Is So Ultra Boring".

Explanation -
Alt + SysRq + r = raw keyboard mode
Alt + SysRq + e = ends all programmes
Alt + SysRq + i = kills all programmes that did not terminate nicely
Alt + SysRq + s = syncs the disks
Alt + SysRq + u = remounts all filesystems as read-only
Alt + SysRq + b = reboots
But for this to work two things are required
Your kernel must support magic keys
The following line must be appended to /etc/sysctl.conf
kernel.sysreq=1
So when your Linux box simply refuses to respond (yes, even a Linux box does sometimes act up), you can safely tide over the situation if you follow these instructions.

How I configured Wireless Internet on my Slackware 12.1 installation!

2008-07-17T12:12:00.000+05:30

I have a Broadcom Wireless card on my Acer Aspire 5100 laptop running Slackware 12.1.
This is how I configured a wireless network -

Downloaded and installed ndiswrapper from Linuxpackages site.
Copied the card drivers from Windows. The drivers are bcmwl5.inf and bcmwl5.sys.
Then I installed the drivers using ndiswrapper as
$ ndiswrapper -i bcmwl5.inf
To check whether the drivers have been properly installed, issue the following command
$ ndiswrapper -l
the driver should be listed here.
Then we have to make sure that /etc/rc.d/rc.netdevice loads ndiswrapper
Edit /etc/rc.d/rc.inet1 to incorporate the wireless card details like essid, key etc.
unload the following modules - b43 and ssb using the following commands
$ sudo modprobe -r b43 ssb
Load bcm43xx and ndiswrapper
$ sudo modprobe bcm43xx
$ sudo modprobe ndiswrapper
Restart the network as
$ sudo /etc/rc.d/rc.inet1 wlan0_restart
Bring up the wlan0 interface as follows -
$ sudo ifconfig wlan0 up

That's it. The wireless internet connection was up and running!

Using ffmepg to convert a '.rm' file to '.mp3' format

2008-07-17T11:49:00.001+05:30

Ffmpeg is a nifty command line utility. Among the various things it can do, converting a '.rm' file to '.mp3' format is one. I was looking for a utility to convert a beautiful Telugu song in .rm format to .mp3 format. Ffmpeg came to my rescue.

I keyed in the following in a terminal and I was through in a jiffy -
$ ffmpeg -i filename.rm filename.mp3