Posts Tagged ‘linuxes’

How to install BlueJeans Video calls, sharing, Conference software on Debian / Ubuntu Linux – Convert RPM to DEB package with alien howto

Tuesday, August 28th, 2018

bluejeans-linux-logo

As I'm currently looking for ways to maximize my incomes without taking participation in 5 days week 8 hours schedule in a Big Corporation office job (which prooved for me to be a terrible slavery) I decided to give Free Lancing a try once again. 
Historically I have registrations in some of the most popular Free Lancing services Web platforms such as freelancer.com and upwork.com.
But none of them really was easy enough to handle as applying and winning a project there is usually a lot of headbanging into the walls and the platforms are full of clients that are looking for free lancers for short-term projects the work selection there required too much work, often projects offered there are seriously under-paid and its really hard to negotiate with many of the clients as they're unprofessional in the fields they're working (don't get me wrong I'm not saying many people are not very successful with this platforms, and that the platforms are not providing work for me I only say it is not really something to my liking …

In the mean time if you happen to read this article and looking for a High Quality Empoyee Cheap System Administrator or automation developmer, an IT counseling FreeLancer or a Ultra cheap WebHosting service in the European Union, I'll be very happy if you become my client.

Anyways … further on I decided to further experiment a little bit with other Free Lancing platforms (suggested by a friend Mitko Ivanov who helped me a lot with things and is continuing to help me over the last year ).

So following his kind suggestion I already tried one of the popular FreeLancing freeeup.com which is looking only for a best specialists into the fields of Marketing, Development, System Administration etc. but even though I tried hard with them the guys decided I am not matching there criteria for a the best 1% of all the people in the field of IT so my application for the platform was rejected twice over the last 1 month and a half.

Another similar new platform for free lancing that looks promising that I've learned about is toptal.com (there site Slogan is Hire FreeLance Talent from the Top 3%) so I went there and registered.

I had hit a road block there too as it seems, there website registration form was not tested enough with non-Windows operating systems with Mozilla Firefox and as it happens that I am using Debian GNU / Linux for my Desktop their drop-down menus was not working, just like some of the form on their website regular expression checks failed.

I've contacted the guys to inform them about their problems (and they kindly advised) I just give a try a registration with different browser (i.e. Google Chrome) which I immediately did and registratoin there was finally a success.
I have to say the new user application form registration of toptal also annoyed me with the stupid requirement to provide a picture in 1000px x 1000px but as this freelancing platform is still new and has way to go until it is established name in the field of freelancing such as upwork.com and I warmly excuse them.

Once registerered for them the user has to schedule an entry interview just like it goes with a standard company interview with a kind of Human Resources (HR) specialist and I guess some technical guys in order to evaluate on your value (Ha-Ha, someone else to determine your value is already crazy but all crazy employees do it still, of course I don't care as I well know that my value is much more than what they put on me).
The online interview once scheduled has to be done in a Web Meeting (Online Rooms) Platform called BlueJeans similar to Cisco WebEx (that is today heavily used in Corporate world in companies such as Hewlett Packard where we used it heavily, IBM, Concentrix etc.) and others Zoom, JoinMe GotoMeeting, HighFive.

As you could guess BlueJeans (which is by the way a Cloud based meeting software – yackes !) is planned to work mainly on Windows and Mac OS Operating Systems and even though there is a BlueJeans Linux version the provided binary is only for RedHat based linuxes in the RPM binary package format, so in order for me to participate in the scheduled meeting, I either had to port the package and install it on my Debian (what triggeted me to write this article or) use a Virtual Machine such as VirtualBox or VMWare running some kind of Windows OS such as Windows 8 / 10 etc.

Even though I have a Windows 10 OS testbed in a Virtualbox container, I preferred to not use it for BlueJeans and do it the hard way and install BlueJeans on my Debian 9.5 Stretch Linux.

That appeared to be a relatively easy process, so below is how I did it:

1. Download alien convertion (tool) that allows you to convert RPM -> deb, Slackware -> Deb and Linux Standard Base (LDB) packages to deb package format

noah:~# apt-get install –yes alien

2. Download latest BlueJeans version from BlueJeans website
 

As of time of writting this article the download link for bluejeans online conferencing software is here

noah:~# wget https://swdl.bluejeans.com/desktop/linux/1.36/1.36.9/bluejeans-1.36.9.x86_64.rpm

3. Convert bluejeans rpm package with alien

noah:~# alien –to-deb bluejeans-*.rpm
 

Warning: Skipping conversion of scripts in package bluejeans: postinst postrm preinst prerm
Warning: Use the –scripts parameter to include the scripts.
bluejeans_1.36.9-2_amd64.deb generated
root@jericho:/home/hipo/Свалени# dpkg -i bluejeans_*.deb
Selecting previously unselected package bluejeans.
(Reading database … 516203 files and directories currently installed.)
Preparing to unpack bluejeans_1.36.9-2_amd64.deb …
Unpacking bluejeans (1.36.9-2) …
Setting up bluejeans (1.36.9-2) …


4. Install the deb package as usual with dpkg tool

noah: ~# dpkg -i bluejeans_*.deb

By default BlueJeans were installed under directory /opt/bluejeans

noah:~# ls -al /opt/bluejeans/bluejeans-bin
-rwxr-xr-x 1 root root 72423392 Jun 14 02:31 /opt/bluejeans/bluejeans-bin*

5. Fix missing library links if such are present in order to make BlueJeans workable

Historically I have dealt with many Linux programs that are provided only in RPM package format and I knew that often once an RPM is converted to DEB with alien due to the package dependency differences on Redhats (CentOS / Fedora etc.) there are problems with missing libraries.

This time this was the case as well, so as usual right after install I did a check up with ldd (print shared object dependencies Linux command) to find out about missing libraries and one library appeared missing.

noah:~# ldd /opt/bluejeans/bluejeans-bin
    linux-vdso.so.1 (0x00007fffa2182000)
    librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fae95f5e000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fae95d5a000)
    libgtk-x11-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0 (0x00007fae95718000)
    libgdk-x11-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0 (0x00007fae95463000)
    libatk-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libatk-1.0.so.0 (0x00007fae9523d000)
    libpangocairo-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libpangocairo-1.0.so.0 (0x00007fae95030000)
    libgdk_pixbuf-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgdk_pixbuf-2.0.so.0 (0x00007fae94e0c000)
    libcairo.so.2 => /usr/lib/x86_64-linux-gnu/libcairo.so.2 (0x00007fae94aef000)
    libpango-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libpango-1.0.so.0 (0x00007fae948aa000)
    libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007fae945f5000)
    libfontconfig.so.1 => /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007fae943b2000)
    libgobject-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 (0x00007fae9415e000)
    libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007fae93e48000)
    libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007fae93b0a000)
    libXi.so.6 => /usr/lib/x86_64-linux-gnu/libXi.so.6 (0x00007fae938fa000)
    libnss3.so => /usr/lib/x86_64-linux-gnu/libnss3.so (0x00007fae935b1000)
    libnssutil3.so => /usr/lib/x86_64-linux-gnu/libnssutil3.so (0x00007fae93381000)
    libsmime3.so => /usr/lib/x86_64-linux-gnu/libsmime3.so (0x00007fae93154000)
    libplc4.so => /usr/lib/x86_64-linux-gnu/libplc4.so (0x00007fae92f4f000)
    libnspr4.so => /usr/lib/x86_64-linux-gnu/libnspr4.so (0x00007fae92d10000)
    libgconf-2.so.4 => /usr/lib/x86_64-linux-gnu/libgconf-2.so.4 (0x00007fae92adf000)
    libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007fae928ad000)
    libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007fae9269b000)
    libXfixes.so.3 => /usr/lib/x86_64-linux-gnu/libXfixes.so.3 (0x00007fae92495000)
    libXrender.so.1 => /usr/lib/x86_64-linux-gnu/libXrender.so.1 (0x00007fae9228b000)
    libXcomposite.so.1 => /usr/lib/x86_64-linux-gnu/libXcomposite.so.1 (0x00007fae92088000)
    libasound.so.2 => /usr/lib/x86_64-linux-gnu/libasound.so.2 (0x00007fae91d8a000)
    libXdamage.so.1 => /usr/lib/x86_64-linux-gnu/libXdamage.so.1 (0x00007fae91b87000)
    libXtst.so.6 => /usr/lib/x86_64-linux-gnu/libXtst.so.6 (0x00007fae91981000)
    libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fae91763000)
    libcap.so.2 => /lib/x86_64-linux-gnu/libcap.so.2 (0x00007fae9155d000)
    libudev.so.0 => not found
    libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007fae9130c000)
    libnotify.so.4 => /usr/lib/x86_64-linux-gnu/libnotify.so.4 (0x00007fae91104000)
    libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fae90d85000)
    libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fae909f2000)
    libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fae907db000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fae90421000)
    /lib64/ld-linux-x86-64.so.2 (0x00007fae96166000)
    libgmodule-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgmodule-2.0.so.0 (0x00007fae9021d000)
    libgio-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0 (0x00007fae8fe7f000)
    libpangoft2-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libpangoft2-1.0.so.0 (0x00007fae8fc6a000)
    libfribidi.so.0 => /usr/lib/x86_64-linux-gnu/libfribidi.so.0 (0x00007fae8fa53000)
    libXinerama.so.1 => /usr/lib/x86_64-linux-gnu/libXinerama.so.1 (0x00007fae8f850000)
    libXrandr.so.2 => /usr/lib/x86_64-linux-gnu/libXrandr.so.2 (0x00007fae8f645000)
    libXcursor.so.1 => /usr/lib/x86_64-linux-gnu/libXcursor.so.1 (0x00007fae8f43b000)
    libpng16.so.16 => /usr/lib/x86_64-linux-gnu/libpng16.so.16 (0x00007fae8f208000)
    libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fae8efea000)
    libpixman-1.so.0 => /usr/lib/x86_64-linux-gnu/libpixman-1.so.0 (0x00007fae8ed44000)
    libxcb-shm.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007fae8eb41000)
    libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007fae8e919000)
    libxcb-render.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007fae8e70b000)
    libthai.so.0 => /usr/lib/x86_64-linux-gnu/libthai.so.0 (0x00007fae8e501000)
    libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1 (0x00007fae8e2fa000)
    libffi.so.6 => /usr/lib/x86_64-linux-gnu/libffi.so.6 (0x00007fae8e0f1000)
    libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007fae8de7f000)
    libplds4.so => /usr/lib/x86_64-linux-gnu/libplds4.so (0x00007fae8dc7b000)
    libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007fae8da79000)
    libdbus-glib-1.so.2 => /usr/lib/x86_64-linux-gnu/libdbus-glib-1.so.2 (0x00007fae8d851000)
    libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007fae8d5c9000)
    libselinux.so.1 => /lib/x86_64-linux-gnu/libselinux.so.1 (0x00007fae8d3a1000)
    libresolv.so.2 => /lib/x86_64-linux-gnu/libresolv.so.2 (0x00007fae8d18a000)
    libmount.so.1 => /lib/x86_64-linux-gnu/libmount.so.1 (0x00007fae8cf31000)
    libharfbuzz.so.0 => /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0 (0x00007fae8cc81000)
    libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007fae8ca7d000)
    libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007fae8c877000)
    libdatrie.so.1 => /usr/lib/x86_64-linux-gnu/libdatrie.so.1 (0x00007fae8c66f000)
    liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007fae8c449000)
    liblz4.so.1 => /usr/lib/x86_64-linux-gnu/liblz4.so.1 (0x00007fae8c22c000)
    libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007fae8bf10000)
    libblkid.so.1 => /lib/x86_64-linux-gnu/libblkid.so.1 (0x00007fae8bcc1000)
    libgraphite2.so.3 => /usr/lib/x86_64-linux-gnu/libgraphite2.so.3 (0x00007fae8ba94000)
    libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007fae8b87d000)
    libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007fae8b65d000)


As I am on my notebook with Debian 9 and on Debian / Ubuntus and other Linuxes udevd daemon and connected libraries are long time existing, it was obvious the problems to dependencies are because of missing library links (or library version inconsistencies).

To find out what kind of libudev.so* are present I used slocate package (locate) command.

noah:~# locate libudev.so
/lib/i386-linux-gnu/libudev.so.1
/lib/i386-linux-gnu/libudev.so.1.6.10
/lib/x86_64-linux-gnu/libudev.so
/lib/x86_64-linux-gnu/libudev.so.1
/lib/x86_64-linux-gnu/libudev.so.1.6.10

Obviously the missing library libudev.so.0 was present under a different name so I give a try to just create a new symbolic link from libudev.so.1 to libudev.so.0 hoping that the libudev library version Blue Jeans was compiled against did not have a missing binary objects from the ones installed on my OS.

noah:~# ln -sf /lib/x86_64-linux-gnu/libudev.so.1 /lib/x86_64-linux-gnu/libudev.so.0

noah:~# ldd /opt/bluejeans/bluejeans-bin |grep -i 'not found'

Above command did not return any missing libraries, so I went further and executed it.

6. Go start BlueJeans and register a user or use the anonymous login to be ready for the scheduled online meting

… And, Guess, what it works! 🙂
 

noah:~# /opt/bluejeans/bluejeans-bin

To make it easy to remember to later start the binary under a familiar name, I've also created a link into

noah:~# ln -sf /opt/bluejeans/bluejeans-bin /usr/bin/bluejeans
 

noah:~#  sudo su – hipo
hipo@noah:~$ /usr/bin/bluejeans

bluejeans-video-conferencing-online-sharing-meeting-software-running-on-debian-gnu-linux-screenshot
 

Linux: Configure Midnight Commander to use mcedit instead of nano or vi text editor

Friday, June 21st, 2013

reverting mc text editor to mcedit fix problem with mcedit not working in linux

I use Midnight Commander console file manager on any UNIX like servers, since my early days as system administrator. mc comes with its own text editor mcedit which is often very handy for reading config files or pieces of source code. Many times I had to modify files which were spitting errors which I couldn't track in VIM, jor or whatever text editor had on server at hand and after checking file with mcedit I caught my config or source code mistake. I guess many other admins has similar nice experiences with mcedit Internal file editor of GNU Midnight Commander. Nowadays, I install mostly Debian Linux on new configured servers and using mc to navigate in file system is very useful. I prefer mc to open files for edit with F4 (Edit – kbd shortcut) with its default mcedit, however for some reasons most of Debian / Ubuntu and other Linuxes, nowadays has set global environment text editor to nano. I totally dislike this text editor and like changing mc always to use mcedit. This is done straight from MC menus by:

Pressing F9 -> Going to Options -> Configuration -> (Setting mark on) -> Use Inernal Edit
/code>

unix terminal file manager midnight commander configuration menu screenshot

linux console file manager midnight commander use internal edit menu unchecked screenshot

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How to increase brightness on Fujitsu Siemens Amilo PI22515 notebook with Slackware Linux

Friday, March 9th, 2012

Increase LCD screen brightness on Fujitsu Siemens Amilo laptop with Linux Slackware

A friend of mine has Fujitsu Siemens Amilo laptop and is full time using his computer with Slackware Linux.

He is quite happy with Slackware Linux 13.37 on the laptop, but unfortunately sometimes his screen brightness lowers. One example when the screen gets darkened is when he switch the computer on without being plugged in the electricity grid. This lowered brightness makes the screen un-user friendly and is quite tiring for the eye …

By default the laptop has the usual function keys and in theory pressing Function (fn) + F8 / F7 – should increase / decrease the brightness with no problems, however on Slackware Linux (and probably on other Linuxes too?), the function keys are not properly recognized and not responding whilst pressed.
I used to have brigtness issues on my Lenovo notebook too and remember how irritating this was.
After a bit of recalling memories on how I solved this brightness issues I remembered the screen brigthness on Linux is tunable through /proc virtual (memory) filesystem.

The laptop (Amilo) Fujitsu Siemens video card is:

lspci |grep -i vga
00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) (rev 03)

I took a quick look in /proc and found few files called brightness:
 

  • /proc/acpi/video/GFX0/DD01/brightness
  • /proc/acpi/video/GFX0/DD02/brightness
  • /proc/acpi/video/GFX0/DD03/brightness
  • /proc/acpi/video/GFX0/DD04/brightness
  • /proc/acpi/video/GFX0/DD05/brightness

cat-ting /proc/acpi/video/GFX0/DD01/brightness, /proc/acpi/video/GFX0/DD03/brightness, /proc/acpi/video/GFX0/DD04/brightness all shows not supported and therefore, they cannot be used to modify brightness:

bash-4.1# for i in $(/proc/acpi/video/GFX0/DD0{1,3,4,5}/brightness); do \
cat $i;
done
<not supported>
<not supported>
<not supported>
<not supported>

After a bit of testing I finally succeeded in increasing the brightness.
Increasing the brightness on the notebook Intel GM965 video card model is done, through file:

/proc/acpi/video/GFX0/DD02/brightness

To see all the brightness levels the Fujitsu LCD display supports:

bash-4.1# cat /proc/acpi/video/GFX0/DD02/brightness
levels: 13 25 38 50 63 75 88 100
current: 25

As you can see the dark screen was caused cause the current: brightness is set to a low value of 25.
To light up the LCD screen and make the screen display fine again, I increased the brightness to the maximum level 100, e.g.:

bash-4.1# echo '100' > /proc/acpi/video/GFX0/DD02/brigthness

Just for the fun, I've written also a two lines script which gradually increases LCDs brightness 🙂

bash-4.1# echo '13' > /proc/acpi/video/GFX0/DD02/brightness;
bash-4.1# for i in \
$(cat /proc/acpi/video/GFX0/DD02/brightness|grep 'levels'|sed -e 's#levels:##g'); do \
echo $i > /proc/acpi/video/GFX0/DD02/brightness; sleep 1; \done

fujitsu_siemens_brightness_fun.sh script is fun to observe in changing the LCD screen gradually in one second intervals 🙂

Here is also a tiny program that reduces and increases the notebook laptop brightness written in C. My friend Dido, coded it in just few minutes just for the fun 🙂
To permanently solve the issues with darkened screen on boot time it is a good idea to include echo '100' > /proc/acpi/video/GFX0/DD02/brigthness in /etc/rc.local:

bash-4.1# echo '100' > /proc/acpi/video/GFX0/DD02/brigthness

I've also written another Universal Linux Increase laptop screen brightness Shell script which should be presumable also working for all Laptop models running Linux 🙂

My maximize_all_linux_laptops_brightness.sh "universal increase Linux brightness" script is here
I'll be glad to hear from people who had tested the script on other laptops and can confirm it works fine for them.
 

Fix audioCD play problems with VLC on GNU Linux

Monday, January 23rd, 2012

I've not played audio CD for ages. Anyways I had to set up one computer with Linux just recently and one of the requirements was to be able to play audiocds.
I was surprised that actually a was having issue with such as simple tasks.
Here is how i come with this article.

If you encounter errors playing Audio CDs on any Linux distro in VLC or other players, you might need to apply the following fix.

root@xubuntu-desktop:~# apt-get install xubuntu-restricted-extras
...
root@xubuntu-desktop:~# apt-get install ubuntu-restricted-extras
...

I'm not sure if this packages are required, anyways having them installed is a good idea especially on computers which will have to support as much multimedia as possible.

Trying to play a CD with VLC the result was not nice, you see in the picture above the error that poped up while trying it with VLC:

Due to wrong configuration of the play device VLC will be looking to read the audio cd from.

To succesfully play the audiocd invoke VLC command with a cdda///dev/sr0 argument like so:

hipo@xubuntu-desktop:~$ vlc cdda:///dev/sr0
...

To permanently fix the error you will have to edit ~/.config/vlc/vlcrc :

Inside ~/.config/vlc/vlcrc find the lines:

dvd=/dev/cdrom

Substitute the above line with:

dvd=/dev/sr0

Next find the line:

vcd=/dev/cdrom

Change the above line with:

vcd=/dev/sr0
Due to a bug in generating vlcrc , the dvd= might be set also to other messy unreadable characters (different from /dev/cdrom). This can also be the reason why it fails to properly read the disc.

If dvd= and vcd is set to a different unreadable characters delete them and substitute with /dev/sr0 .I've experienced this on Xubuntu Linux with a Bulgarian localization (probably the bug can be seen in other Linuxes when GNOME is installed in Russian, Chineese and other UTF-8 languages.

The strange error can be observed also in other players when the localization is set to someone's native language …
Alternative solution is to install and use rhythmbox instead of VLC.
Other program to play audio CDs called workman , you will have to get used to the interface which uses gtk1 and therefore obsolete. Putting aside the ugly interface it works 😉

How to play Audio music CDs in GNU/Linux and Free/Net/Open BSDs

Sunday, January 22nd, 2012

If you still have some old dusty CDs left on the CD shelf, its quite cool to give it a ride in a rainy morning.

As I enjoy working in console so much, I thought it might be interesting to share how music audio CDs can be listened in plain text mode console.

For all console / terminal geeks Linux and BSDs can be equipped with a number of text/console audio cd console players.

There are plenty of free software console cd audio players on the net, however I found cdplay , cdcd and dcd to be the most popular ones.

On Debian and Ubuntu G*/Linuces cdplay and cdcd are installable via apt. To install cdtool:

root@xubuntu-desktop:~# apt-get install cdtool
...

cdtool package, contains a number of commands enabling you to listen/stop/shuffle/eject/get info about cd audio volumes. cdtool provides the following binaries:

cdeject
cdclose
cdir
cdinfo
cdpause
cdplay
cdstop
cdvolume
cdshuffle

Install cdcd on Debian and alike by typing:

root@xubuntu-desktop:~# apt-get install cdcd
...

cdcd has shell like interface the most basic use of it is with:

root@xubuntu-desktop:~# cdcd
cdcd> play

To play audiocds in console on FreeBSD , a command tool dcd is available and installable through ports.
To install it issue:

root@freebsd# cd /usr/ports/audio/dcd
root@freebsd# make install clean
...

dcd is also available for Linux but on most GNU/Linuxes it has to be built from source.

Lets say you'd like to Play the 5th song from audio CD:

freebsd# dcd 5

dcd has plenty of great arguments, to get some fun with it check the man page.

Another program that can be used to play audio CDs on both Linux and BSDs is the "classical" mplayer .

To play AUDIO CD with mplayer the command line to use is:

root@debian:~# mplayer -cdrom-device /dev/sr0 cdda:// -cache 5000
...

The argument -cache 5000 has to be passed to to work around choppy sound (if for example audio playback interruptions every few milliseconds).

For people who are keen on ncurses (Midnight Commander) like command line interfaces you might enjoy Herrie a minimalistic music player that supports plenty of sound formats, including audiocds.

Herrie is available for Debian and most deb based modern distros via apt, e.g.:

root@xubuntu-desktop:~# apt-get install herrie
...

Herrie Minimalistic Music player for Linux and BSD


Ports are also available for FreeBSD, NetBSD and OpenBSD.
To install on FreeBSD:

root@freebsd# cd /usr/ports/audio/herrie
root@freebsd# make install clean

I'll be happy to hear feedback and recommendations on any other console audio cd players I might forgot to mention.
Which is your favourite console text based cd audio player?

How to find out which processes are causing a hard disk I/O overhead in GNU/Linux

Wednesday, September 28th, 2011

iotop monitor hard disk io bottlenecks linux
To find out which programs are causing the most read/write overhead on a Linux server one can use iotop

Here is the description of iotop – simple top-like I/O monitor, taken from its manpage.

iotop does precisely the same as the classic linux top but for hard disk IN/OUT operations.

To check the overhead caused by some daemon on the system or some random processes launching iotop without any arguments is enough;

debian:~# iotop

The main overview of iostat statistics, are the:

Total DISK READ: xx.xx MB/s | Total DISK WRITE: xx.xx K/s
If launching iotop, shows a huge numbers and the server is facing performance drop downs, its a symptom for hdd i/o overheads.
iotop is available for Debian and Ubuntu as a standard package part of the distros repositories. On RHEL based Linuxes unfortunately, its not available as RPM.

While talking about keeping an eye on hard disk utilization and disk i/o’s as bottleneck and a possible pitfall to cause a server performance down, it’s worthy to mention about another really great tool, which I use on every single server I administrate. For all those unfamiliar I’m talking about dstat

dstat is a – versatile tool for generating system resource statistics as the description on top of the manual states. dstat is great for people who want to have iostat, vmstat and ifstat in one single program.
dstat is nowdays available on most Linux distributions ready to be installed from the respective distro package manager. I’ve used it and I can confirm tt is installable via a deb/rpm package on Fedora, CentOS, Debian and Ubuntu linuces.

Here is how the tool in action looks like:

dstat Linux hdd load stats screenshot

The most interesting things from all the dstat cmd output are read, writ and recv, send , they give a good general overview on hard drive performance and if tracked can reveal if the hdd disk/writes are a bottleneck to create server performance issues.
Another handy tool in tracking hdd i/o problems is iostat its a tool however more suitable for the hard core admins as the tool statistics output is not easily readable.

In case if you need to periodically grasp data about disks read/write operations you will definitely want to look at collectl i/o benchmarking tool .Unfortunately collect is not included as a packaget for most linux distributions except in Fedora. Besides its capabilities to report on servers disk usage, collect is also capable to show brief stats on cpu, network.

Collectl looks really promosing and even seems to be in active development the latest tool release is from May 2011. It even supports NVidia’s GPU monitoring 😉 In short what collectl does is very similar to sysstat which by the way also has some possibilities to track disk reads in time.  collectl’s website praises the tool, much and says that in most machines the extra load the tool would add to a system to generate reports on cpu, disk and disk io is < 0.1%.  I couldn’t find any data online on how much sysstat (sar) extra loads a system. It will be interesting if some of someone concluded some testing and can tell which of the two puts less load on a system.

Few sshd server Security Tips that will improve your server security

Monday, May 2nd, 2011

On each and every newly installed Linux or FreeBSD server. I’m always very cautious about three configuration directives for the ssh server.
This are X11Forwarding , Protocol and PermitRootLogin

One needs to be very watchful about this three ones, as tuning the right values surely prevents the server from many of the security issues that might rise up with the SSH server.

Many Linuxes like Debian and Ubuntu comes with X11Forwarding yes e.g. (X11Forwarding) enabled by default, this is an useless option in most of the cases as the servers I do administrate does not run a X environment.

Some older Linux distributions I have dealt with has the ssh Protocol 1 enabled by default and therefore, whether I do inherit an old server I have to start administrating the first thing I do is to check if the /etc/ssh/sshd_config‘s Protocol 1 option is enabled and if it is enabled I disable it.

PermitRootLogin is also an option which I often turn off as logging in via remote ssh is potentially dangerous as root password might get sniffed.

In overall the 3 sshd option’s I do check out in /etc/sshd/sshd_config on each newly installed Linux server are:

X11Forwarding yes
PermitRootLogin yes
Protocol 1

I always change this three options in my /etc/sshd/sshd_config
to:

X11Forwarding no
PermitRootLogin no
Protocol 2

One other options sshd server options which is good to be tuned is:

LoginGraceTime 120

Decreasing it to:

LoginGraceTime 60

is generally a good idea.

Of course after the changes I do restart the ssh daemon in order for the new configuration to take place:

linux:~# /etc/init.d/sshd restart
...

Fixing / Resolving Fullscreen Adobe Flash issues in Debian Linux

Monday, April 11th, 2011

Adobe Flash Player ugly Logo!

If you’re experiencing problems with maximising flash (let’s say youtube) videos on your Debian or Ubuntu or any other debian derivative.
You’re not the only one! I myself has often experienced the same annoying issue.

The flash fullscreen failures or slownesses are caused by flash player’s attempts to use directly your machine hardware, as Linux kernel is rather different than Windows and the guys from Macromedia are creating always a way more buggy port of flash for unix than it’s windows versions, it’s quite normal that the flash player is unable to properly address the computer hardware on Linux.

As i’m not programmer and I couldn’t exactly explain the cause for the fullscreen flash player mishaps, I’ll skip this and right give you the two command lines solution:

debian:~# mkdir /etc/adobe
debian:~# echo "OverrideGPUValidation = 1" >> /etc/adobe/mms.cfg

This should fix it for, you now just restart your Icedove (Firefox), Epiphany Opera or whatever browser you’re used to and launch some random video in youtube to test the solution, hopefully it should be okay 😉 But you never know with flash let’s just hope that very soon the open flash alternative gnash will be production ready and at last we the free software users will be freed from the evil “slavery” of adobe’s non-free flash player!
Though this tip is tested on Debian based Linux distributions it should most likely work same in all kind of other Linuxes.

The tip should also probably have effect in FreeBSD, though the location of the adobe directory and mms.cfg should probably be /usr/local/etc/adobe, I’ll be glad to hear from some FreeBSD user if including the OverrideGPUValidation = 1 flash option to mms.cfg like below:

# mkdir /usr/local/etc/adobe
# echo "OverrideGPUValidation = 1" >> /usr/local/etc/adobe/mms.cfg

would have an impact on any flash player fullscreen issues on FreeBSD and other BSD direvative OSes that run the linux-flash port.