Radio Tray can be launched from “Sound & Video” menu under “Applications”. It will appear in the system tray area. This is the beauty of this software that as it runs in system tray so it does not consumes much system resources as it does not require any browser window or any other heavy application to function. Radio Tray will launch in system tray and will not automatically play any station. To play the radio station, click on the Radio Tray (tray) icon and select the station from drop down list (you may require extra plugins for proper functioning of the application e.g gstream libraries).

Perhaps the pre-configured radio stations may not interest you. You can not only add your favourite channels but even Remove or Edit any existing channel. To Add/Remove channel(s) in Radio Tray, Right Click on the tray icon and Select “Configure radios…”. A dialogue box will appear. Here you can Add new channels, Remove or Edit existing channels and Move the Channels UP or Down in the list. Lets, now add a radio station to Radio Tray. Go to: http://www.shoutcast.com/ and search for some radio station (say, rock). From the results, just copy the link of any radio station. Now come back to “Configure Radios” and Click on “Add” Button. In the “Radio name” box enter any friendly name (say Soft Rock) of the radio station while in the “URL” paste the link of the radio station.

Your new radio station is now added into the channel lists of Radio Tray and you can listen to it just by selecting it from the drop down list of Radio Tray.

If your favorite station doesn’t have a standard M3U or PLS playlist posted on their web site, you can always find the stream’s URL by other means. Radio Tray isn’t incredibly feature-filled, but on those occasions you just need a simple unitasker, it’s perfect for getting the job done and staying out of your way. Its a perfect substitute for proprietary radio softwares and not only available in .deb format but also in source format.

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Radio Tray – A Radio Player That Fits In System Tray originally appeared on Yet Another Linux Blog on April 25, 2011.

Normally I don’t like to manually install things outside the repository because when updates are pushed, there is no upstream source to differentiate from…so your chances of running outdated software increase unless you are vigilant.  Luckily, I consider myself vigilant.  Unfortunately, I’m not as vigilant as I consider myself to be…so I’ve added in reminders for myself on my Google calendar to check for Firefox 4 updates.

So, here’s how to get Firefox 4 onto your LMDE desktop…First, uninstall the version of Firefox you have using Synaptic or the software center.  Open a terminal up and let’s get started.

Create a temporary directory to house a downloaded and unzipped Firefox:

cd ~/ && mkdir tmp && cd tmp/

Next, let’s download and unzip it (please note this is for en-US version only…you’ll have to adjust the URL for diff. languages):

32bit

wget http://releases.mozilla.org/pub/mozilla.org/firefox/releases/latest-4.0/linux-i686/en-US/firefox-4.0.tar.bz2

64bit

wget http://releases.mozilla.org/pub/mozilla.org/firefox/releases/latest-4.0/linux-x86_64/en-US/firefox-4.0.tar.bz2

Now let’s unzip and extract it:

tar -xvjf firefox*.tar.bz2

Now let’s move the newly extracted items to /usr/local so it can be used by the system:

sudo mv firefox /usr/local/firefox4

Now we need to create a link so that applications calling firefox 4 access it correctly:

sudo ln -s /usr/local/firefox4/firefox /usr/local/bin/firefox4

Ok, the hard part is done…but you don’t have a menu entry for it nor a shortcut you can execute.  Let’s do that now.  Right click your mint menu and choose “edit menu”.  Now, select the “Internet” menu in the left hand pane.  Click the “New Item” button.  The following window will pop up…fill it in with the information contained in the picture below:

The command line should be (remember the link we made above? let’s use it!):

/usr/local/firefox4/firefox %u

Notice in the picture above the Firefox icon is present…yours most likely isn’t.  In order to set the icon, click the area where it appears above and then select the following image:

When you’re finished, click close.  Firefox 4 should now appear under “Internet” in your Mint Menu.  You can now right click that item and add it to your favorites if you wish.

Now let’s make sure you list Firefox 4 as the default web browser for Gnome.  Do this by opening up the control center in the Mint Menu.  Select “Preferred Applications” inside the control center.  Make sure that you choose ‘custom’ in the drop down menu shown below and the path for the command will be the same as it was for your launcher but instead of a %u you can use a %s at the end of the command (as shown in the picture below):

That should be everything you need to have a good Firefox 4 experience in LMDE.  To uninstall things, you can simply delete the menu items and then delete the directories we created during the install process.

Hopefully this will help those of you out there who want Firefox 4 on your LMDE install!

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Install Firefox 4 on Linux Mint Debian Edition (LMDE) originally appeared on Yet Another Linux Blog on April 1, 2011.

‘tail’ can be used alone or can be combined with other commands like ‘grep’, ‘ls’ etc.

To use ‘tail’, let’s first create a text file. You can create the file by issuing following command in terminal;

touch my_file

Now open my_file with your favorite text editor (nano in my case) and write some lines. For this article, I have written the following 15 lines;

this is the 1st line
this is the 2nd line
this is the 3rd line
this is the 4th line
this is the 5th line
this is the 6th line
this is the 7th line
this is the 8th line
this is the 9th line
this is the 10th line
this is the 11th line
this is the 12th line
this is the 13th line
this is the 14th line
this is the 15th line

Now issue the following command in terminal;

tail my_file

It will print the last 10 lines which would be the “this is the 6th line” through “this is the 15th line”.

You can control the number of lines which ‘tail’ will print. You can either increase or decrease the number of lines. For example, if you want ‘tail’ to show only last 3 lines, you can do this by issuing the following command;

tail -n 3 my_file

Now it will print only last 3 lines. You can use any number of lines instead of 3. Or you can use a plus sign like;

tail -n+7 my_file

‘tail’ will start printing from 7th line to the end of the file.

You can view the desired file with respect to size. Issue the following command in terminal;

tail -c 14 my_file

And it will show the output of last 14 bytes. In my case, the output was;

the 15th line

‘tail’ not only displays the static output of a file but it can also monitor the file for changes. A ‘-f’ option is used with ‘tail’ and it starts acting like a monitoring tool which not only displays the last few lines but also constantly updates the output as the file changes. Here is a very popular example;

tail -f /var/log/message

‘tail’ will print the last 10 lines of ‘message’ file. If you now plug-in you USB stick, you will notice that the change in ‘message’ file will instantly be reported by ‘tail’. To release the cursor press Ctrl+c.

There are many other useful options which you can use with ‘tail’ like;

tail -q my_file        # never output headers

tail -v my_file        # always outputs headers

You can combine ‘tail’ with other utilities like ‘ls’, ‘grep’, ‘head’ etc.

You can combine ‘tail’ with ‘grep’ to get lines with some specific ‘word’.

tail -n 5 my_file | grep 14

It will print only those lines out of last 5 which contains the word ’14′. In my case the output was:

this is 14th line # ’14′ will be highlighted

‘tail’ can also be combined with ‘ls’ to get the list of last few files/folders. For example, if you issue the following command;

ls -l | tail -n 2

It will give a long listing of files/folders but will show the last 2 entries of the working directory.

These are just two examples of combining ‘tail’ with other utilities. There are countless examples of combination of ‘tail’ and other softwares.

‘GNU tail’ is a very handy tool. It can output any amount of data depending upon the options used. It makes the work of an ordinary user much easer and helps him/her find information in files more efficiently. To become an expert in Linux, this is a mandatory utility over which a user must have complete mastery. Hopefully, this tutorial gets you started chasing your tail!

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Chasing Your ‘Tail’ With Linux originally appeared on Yet Another Linux Blog on January 27, 2011.

You may be thinking about some way to avoid typing commands over and over. Enter the ‘alias’.

The ‘alias’ tool is a way to make the complicated things simple (and simple things simpler). You can use ‘alias’ instead of long (or even short) commands.  Now let’s see how the ‘alias’ works.

‘alias’ can make difficult and lengthy commands easy. The general format of ‘alias’ is:

alias Any_Word=”Command”

It means you linked an existing command to a (New) Word. This ‘Any_Word’ may contain anything – any alpha-numeric symbol, ‘Any_Word’ as well as ‘Command’ are interchangeable and can be used for the same purpose.

Simple Commands Made Simpler

As an example, ‘ls -l’  is used for listing directory contents in ‘long listing format’. This ‘ls -l’ can be replaced with a simpler alias. You can set the ‘alias’ for ‘ls –l’ as follows:

alias ll=”ls –l”

Now you just have to type ‘ll’ (without quotes) to get ‘long listing format’.

Or if you frequently misspell ‘ls’ as ‘sl’ and don’t want to install ‘sl’ package, then, you can use the following alias:

alias sl=”ls”

Now, whenever you type ‘sl’ in terminal, it will give you same results as ‘ls’.

Now consider even simpler example. To close a Terminal (or logout), you have to type ‘exit’ in Terminal. This ‘exit’ command can be made even simpler by using the following ‘alias’:

alias x="exit"

Now, you only have to type ‘x’ in Terminal to ‘exit’

Other examples of ‘alias’ are:

alias cp="cp -iv"
#make copy operation interactive and verbose

alias rm="rm -iv"
#make remove operation interactive and verbose

alias mv="mv -iv"
#make move operation interactive and verbose

Make Package Management A Bit Simpler

If you use Debian (or its derivatives) then you will be familiar with APT.  It is an excellent package manager.

In Ubuntu, to install software using APT, you have to use the following command:

sudo apt-get install <sofware_name>

It is a long command and consumes a lot of your time and energy

You can shorten this command by using ‘alias’.  Issue the following command in Terminal:

alias Install=”sudo apt-get install”

You can obviously use your own word instead of ‘Install’.

Now, you just have to type:

Install <software_name>

to install the (same) software. Simple, isn’t it?

You can simplify other aspects of APT. For example, you can use the following ‘alias’:

alias Remove=”sudo apt-get remove”

to uninstall a software.

Some other examples of attaching APT with ‘alias’ are:

alias Update=”sudo apt-get update”

alias Upgrade=”sudo apt-get upgrade”

alias Search=”apt-cache search”

alias Autoremove=”sudo apt-get autoremove”

alias Autoclean=”sudo apt-get autoclean”

alias Purge=”sudo apt-get remove –purge”

and so on…

A Very Interesting ‘alias’ For A Difficult Keyboard Button

On some keyboards, the dot (.) button is at very difficult position and if you have to use it more than once, it becomes even more difficult.  That’s why ‘cd ..’ is the command which I mistype the most.  This complication can be easily removed by using following ‘alias’ (you can use any other word instead of a dot):

alias .=”cd ..”

alias ..=”cd ../..”

alias ...=”cd ../../..”

alias ....=”cd ../../../..”

Using Internet From Terminal

If you regularly use lynx to browse the internet in terminal then you have to type long urls with lynx to visit the web pages.  You can simplify these long urls by using ‘alias’:

alias Google=”lynx http://www.google.com/”

alias Yahoo=”lynx http://www.yahoo.com/”

alias yalb =”lynx http://linux-blog.org/”

and so on…

Now just type Google, Yahoo or yalb to visit the respective web sites.

Simple ‘alias’ For More Complicated Commands

Long commands are not only difficult to remember but also take more time to type; when you have to use them on daily basis, you become frustrated when typing them again and again and again… So, ‘alias’ are more suitable for long and complicated commands.

Let’s consider an example.

To find the top 10 largest files in your system, you can set the following ‘alias’:

alias top10files=”find . -type f -exec ls -sh {} \; | sort -n -r | head -10”

You can even mix different commands with ‘alias’.  For instance, if you regularly use ‘tail’ and direct its output to file to later view that file, you can set a very simple ‘alias’ to do this cumbersome operation in 1 word:

alias Tail=”tail /var/log/messages > hello.txt;cat hello.txt”

Now just enter ‘Tail’ and viola! All is done at once.

You can use any file with tail and direct its output and you can even use ‘nano’ or ‘vi’ to view/edit its output.

Here’s another example… ‘alias’ to connect to a remote server:

alias any_name=”ssh <remote_server_address> -l <username> -p <port>”

You can even create ‘alias’ for your bash scripts, like:

alias clc=”sh /home/user/myscripts/calc.sh”

Now that you have set a few different ‘alias’  you might want to check that which ‘alias’ are set on your system.  To do that, just issue the following command:

alias

and it will list all the set ‘alias’ you have.

To remove an ‘alias’, just issue the ‘unalias’ command, like:

unalias Google

and now typing Google in terminal will do nothing (as it was set with lynx).

To remove all the ‘alias’, issue the following command and all the ‘alias’ are gone:

unalias –a

We have discussed the way of setting the ‘alias’ for different kinds of commands.  But setting ‘alias’ in this way be temporary.  When you reboot you PC, all the ‘alias’ which you have set will be gone.  This does not mean that you have to set all the ‘alias’ every time you boot your PC.  If you have set an ‘alias’ and you liked it so much that you want it to permanently reside in you PC, just add this alias in ‘.bashrc’ file in you home directory. For example, if you want ‘alias’:

Install <software_name>

to permanently reside in your PC then user your favorite text editor and add the following line in your ‘~/.bashrc’ file:

alias Install=”sudo apt-get install”

Now this ‘alias’ will not vanish into thin air when you reboot your PC. Only those ‘alias’  which are listed in ‘~/.bashrc’ file will be permanent.

This guide is just a preview about ‘alias’.  It is just about basic ways of using ‘alias’ to make your life simpler.  ‘GNU alias’ is a tool which can simplify your life immensely.  But unfortunately this tool is not given the attention it deserves.  In short, it is such a powerful tool that if you give it proper time, it can make you forget typing

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Using ‘Alias’ in Linux originally appeared on Yet Another Linux Blog on December 23, 2010.

Most people use GUI tools to search for files.  They don’t realize that they can use command line tools to search for them as well! GNU ‘find’ is such like a tool which can not only search files but can even copy, move or delete these files on the fly.

So let’s see that how ‘find’ works.

Find Your Lost Files!

Let’s start from a simple example:

Suppose you want to search for a file named ‘master.txt’ in your home directory.

Open the Terminal and issue the following command:

find . -name “master.txt”

‘find’ will immediately show the results.  If ‘find’ does not show any result, this means that the file, in our case, ‘master.txt’, does not exist.  It is not always the case that you want to find something in you home directory.  The lost/desired file may be anywhere in your computer.  Suppose you want to find a file named ‘space-01.jpg’ and you only know that its located somewhere in /usr directory. You can find it by issuing following command in Terminal:

find /usr -name “space-01.jpg”

and ‘find’ will tell you that this is located under /usr/share/backgrounds.

Using Wildcards

Maybe you want to search for a file but you don’t know its exact name?  Don’t worry!  You can still locate the file using ‘GNU find’ and wildcard will help you in this regard. Wildcards are a way of searching files when you don’t know much about your desired file.

One of the commonly used wildcard is asterisk (*).  Lets consider an example to better understand the things.

Suppose you want to search a file named ‘Jumping_Flowers’ but you only remember the ‘Jumping‘ part of the file name.  So issue the following command in Terminal:

find . -name “Jumping*”

And it will display all the files starting with the word ‘Jumping’.  You can use asterisk (*) anywhere with a file name.  For example:

find . -name “*Jumping*”

And it will display all the files which contains the word ‘Jumping’.

Here are some more examples of use of a wildcard:

find . -name “Jumping*Flowers*”

find . -name “*Jumping*Flowres.mp3”

Searching For Different File Types

Sometimes you are not looking for some specific file but you are looking for a group of files.  For example, you may be looking for all the .txt files in your home directory.  To find all the .txt files, you will give the following command in Terminal:

find . -name *.txt

In case of mp3 files, the above command will be:

find . -name *.mp3

When You Want to Search with Respect to Time

If you want to search for files by the last time they were accessed, you can use -amin flag with ‘find’.  In this case you have to put a minus (-) sign before the time.  The time here is in minutes.  In order to search for .doc files which were accessed in last 10 minutes, you will give the following command:

find . -amin -10 -name "*.doc"

Similarly, to search for .doc files which were modified in last 20 minutes, you will use -mmin option as follows:

find . -mmin -20 -name “*.doc”

Search For Files which are Eating Your Hard Disk

There may be files on your system which are not only huge in size but also located obscure places.  You may also may not know when they were last accessed.  You have to use -size option with ‘find’ to locate them.

Let’s see how we can do this:

find . -size +100M

It will list all those files which are greater than 100 Megabytes.  You can replace ‘M’ with ‘G’ (for Gigabyte) or with ‘k’ (for Kilobyte)

Copy, Move, or Delete Unwanted Files on the Fly

Copy – ‘find’ can also be used to copy or backup your files.  You can use ‘find’ to copy certain files from one location to other with one simple command.

Suppose you want copy all of your mp3 songs from your home directory to your Windows Partition.  Enter the following command in Terminal:

find . -name "*.mp3" -exec cp {} /path/to/Windows_Drive \;

And all of your mp3 files will be copied to the desired Drive/Folder.

Move – There may be situations that you quickly want to move all of your document files from your Hard Disk to your USB to keep them safe.  To move all of your documents from your home directory to your USB, you will issue the following command:

find . -name "*.doc" -exec cp {} /path/to/USB \;

Delete – Suppose there are a lot of .tmp files and you want to get rid of them at once.  Again ‘GNU find’ is at your service and does the work for you.  Issue the following in Terminal and all of the .tmp files are gone…

find . -name '*.tmp' -exec rm {} \;

Which Files are Owned by You and Which Are Not?

There may be a situation when you want to know that which files in some other directories (or even in your home directory) are owned by some other user of your computer.

Suppose there is another user named ‘blackstar’ with whom you are sharing your PC.  Now you want to know that which .doc files in Windows Directory is owned by this user ‘blackstar’.  You can do this by issuing the following command:

find /path/to/Windows_Drive -user blackstar -name “*.doc”

Just replace ‘blackstar’ with your username to search on your system.

Direct the Output of ‘find’ to a File

You can save the results of your ‘find’ command to a text file which will allow you to examine the results in detail at some later time (or to create playlist of your songs).  For this purpose a greater than (>) sign is used (referred to as “piping the command”).

Suppose you want to save the list of all the mp3 songs in your home directory to a text file (which you can later share with your friend), you can do this by:

find . -name "*.mp3" > mp3.txt

It will save the complete path to all of your mp3 songs in the file named mp3.txt.

Find, a Handy Command Line Tool

This article is basically directed towards new users of Linux which are not much familiar with command prompt. This is a small but comprehensive article about ‘GNU find’ . The man pages of ‘find’ list a huge number of options which are difficult to explain in detail in one small article. I tried to cover those option which are commonly used. Obviously, to know more about such a powerful tool , one has to visit its man pages again and again and spend a lot time with ‘find’

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GNU find – A Multidimensional Tool originally appeared on Yet Another Linux Blog on November 24, 2010.

Permissions are important for keeping your data safe and secure.   Utilizing permission settings in Linux can benefit you and those you want to give access to your files and you don’t need to open up everything just to share one file or directory (something Windows sharing often does).  You can group individual users together and change permissions on folders (called directories in Linux) and files and you don’t have to be in the same OU or workgroup or be part of a domain for them to access those files.  You can change permissions on one file and share that out to a single group or multiple groups.  Fine grained security over your files places you in the driver seat in control of your own data.

Some will argue that it may be too much responsibility…that placing this onto the user is foolish and other aforementioned operating systems don’t do this.  You’d be right…XP doesn’t do this.  However, Microsoft saw what Linux and Unix do with the principle of least privilege and have copied this aspect from them.  While the NTFS filesystem employs user access lists with workgroups and domains…it cannot mirror the fine grained, small scale security of Linux for individual files and folders.  For the home user, Linux empowers control and security.

I’m going to go over how users and directory/file permissions work.  So, let’s setup an example that will allow us to explore file permissions.  If you have any questions, just ask it in the comments section at the end of the article.

File Permissions Explained

The picture to your left is a snapshot of my $HOME directory.  I’ve included this “legend” to color code and label the various columns.  Let’s go through the labels and names of things first and then work on understanding how we can manipulate them in the next section.

As noted in the picture, the first column (orange) explains whether or not the contents listed is a directory or not.  If any of these happened NOT to be a directory, a dash (-) would be in place of the d at the beginning of the listing on the far left.

In the second, third, and fourth column (Green, Blue and Red) we find permissions.  Looking at the gray box in the bottom-right corner gives us an explanation of what each letter represents in our first few columns.  These tell us whether or not each user, group, or other (explained in detail later in this article) have read, write, and execute privileges for the file or folder/directory.

In the 5th column (white) the number of hard links is displayed.  This column shows the number of actual physical hard links.  A hard link is a directory reference, or pointer, to a file on a storage volume that is a specific location of physical data.  More information on hard links vs. symbolic (soft) links can be found here.

In column 6 (light blue) we find the user/owner of the file/directory.  In column 7 (gray blue), the group that has access to the file/folder is displayed.  In column 8 (pink), the size of the file or folder is shown in kilobytes.  In column 9 (fluorescent green), the last date the file or folder was altered or touched is shown.  In column 10 (grey), the file or directory name is displayed.

We’re going to pay specific attention to the first four columns in the next section and then follow that up by working with the sixth and seventh by going over user/owner and group.  Let’s move on to go over all of those rwx listings and how we can make them work for us.

Read, Write, Execute – User, Group, Other

First, let’s go over what different permissions mean.  Read permission means you can view the contents of a file or folder.  Write permission means you can write to a file or to a directory (add new files, new subdirectories) or modify a file or directory.  Execute permission means that you can change to a directory and execute ( or run ) a file or script for that file or directory.

The User section shown in green in the picture above shows whether or not the user can perform the actions listed above.  If the letter is present, the user has the ability to perform that action.  The same is true for the Group shown in blue above…if a member of the group that has access to the file or directory looks in this column, they will know what they can or can’t do (read,write, or execute).  Lastly, all others (noted in the red column above).  Do all others have read, write, and execute permissions on the file or folder?  This is important for giving anonymous users access to files in a file server or web server environment.

You can see how fine grained you might be able to set things up with…For example, you may give users read only access while allowing a group of 5 users full control of the file or directory.  You may want to switch that around.  It’s entirely up to you how you want to setup permissions.

More about Groups

Let’s go through setting up a group and adding a few users to it and then assigning that group permissions to access a directory and file.

Create a file inside your home directory by opening up a shell or terminal and typing:

touch ~/example.txt

You’ve now created a file called example.txt inside your home directory.  If you are already there, you can list the contents with the ‘ls’ command.  Do that now.  If you’re not already there, type ‘cd ~/’ and you will be taken to your home directory where you can ‘ls’ list the files.  It should look similar to the following:

[devnet@lostlap ~]$ ls -l
total 40
drwxr-xr-x  2 devnet devnet 4096 2010-05-24 17:04 Desktop
drwxr-xr-x  6 devnet devnet 4096 2010-05-24 13:10 Documents
drwxr-xr-x  9 devnet devnet 4096 2010-05-27 15:25 Download
-rw-rw-r--  1 devnet devnet    0 2010-05-28 10:21 example.txt
drwxr-xr-x 13 devnet devnet 4096 2010-05-26 16:48 Music
drwxr-xr-x  3 devnet devnet 4096 2010-05-24 13:09 Pictures
drwxr-xr-x  3 devnet devnet 4096 2010-05-24 13:04 Videos

Next up, let’s create a new group and a couple of new users.  After creating these we’ll assign the users to the new group.  After that, we’ll move the file and lock it down to the new group only.  If everything works as planned, the file should be accessible to root and the other 2 users but NOT accessible to your current user. You’ll need to be root for all of these commands (or use sudo for them). Since I have sudo and don’t want to continually type sudo, I used the command “sudo -s” and entered my root password to permanently log in as root in a terminal for the duration of this how-to. OK, Let’s get started:

[root@lostlap ~]$ useradd -m -g users -G audio,lp,optical,storage,video,wheel,games,power -s /bin/bash testuser1
[root@lostlap ~]$ useradd -m -g users -G audio,lp,optical,storage,video,wheel,games,power -s /bin/bash testuser2

The above commands will create two users that should be pretty close to your current logged in user (as far as group membership goes).  If the groups you’re adding the user to do not exist, you may get a warning that the groups don’t exist…no worries, just continue.  If the above commands don’t work on your system (I used Arch Linux to do this) then you can use the GUI elements to manage users and add a new one.  You won’t need to add them to any extra groups since we just need a basic user.  Next, let’s create our ‘control’ group.

[root@lostlap ~]$ groupadd testgroup

The above command creates the ‘testgroup’ group. Now let’s add the two users we created to this group.

[root@lostlap ~]$ gpasswd -a testuser1 testgroup
[root@lostlap ~]$ gpasswd -a testuser2 testgroup

The command above adds both our test users to the test group we created. Now we need to lock the file down so that only those users inside of ‘testgroup’ can access it. Since your current logged in user is NOT a member of ‘testgroup’ then you shouldn’t be able to access the file once we lock access to that group.

[root@lostlap ~]$ chgrp testgroup example.txt

The above command changes the group portion of file permission (discussed earlier) from a group your currently logged in user is a member of to our new group ‘testgroup’. We still need to change the owner of the file so a new terminal opened up as your current user won’t be the owner of example.txt.  To do this, let’s assign example.txt a new owner of Testuser2.

[root@lostlap ~]$ chown testuser2 example.txt

Now when you try to access the file example.txt you won’t be able to open it up as your standard user (root still will be able to access it) because you don’t have the permissions to do so. To test this, open up a new terminal (one where you are not root user) and use your favorite text editor and try to open up example.txt.

[devnet@lostlap ~]$ nano example.txt

Both testuser1 and testuser2 will be able to access example.txt because testuser2 owns the file and testuser1 is in the testgroup that has access to this file. However, your current logged in user will also have READ rights to it but will not be able to access it. Why? Let’s take a look at the permissions on example.txt

[devnet@lostlap ~]$ ls -l example.txt
-rw-r--r-- 1 testuser1 testgroup 8 2010-05-28 10:21 example.txt

Notice that the user, group, and other (1st, 2nd, and 3rd position of r,w,x – see the handy diagram I made above) have permissions assigned to them. The user can read and write to the file. The group can read it. Others can also read it. So let’s remove a permission to lock this file down. Go back to your root terminal that is open or ‘sudo -s’ to root again and do the following:

[root@lostlap ~]$ chmod o-r example.txt

Now go back to your user terminal and take a look at the file again:

[devnet@lostlap ~]$ ls -l example.txt
-rw-r----- 1 testuser1 testgroup 8 2010-05-28 10:21 example.txt

Once that has been accomplished, try and open the file with your favorite text editor as your currently logged in user (devnet for me):

[devnet@lostlap ~]$ nano example.txt

Your user now should get a permission denied error by nano (or whatever text editor you used to open it). This is how locking down files and directories works. It’s very granular as you can give read, write, and execute permissions to individual users, groups of users, and the general public. I’m sure most of you have seen permissions commands with 777 or 644 and you can use this as well (example, chmod 666 filename) but please remember you can always use the chmod ugo+rwx or ugo-rwx as a way to change the permissions as well. I liked using letters as opposed to the numbers because it made more sense to me…perhaps you’ll feel the same.

Hopefully you now have a general understanding how groups, users and permissions work and can appreciate how the complexity of it is also elegant at the same time. If you have questions, please fire away in the comments section. Corrections? Please let me know! Thanks for reading!

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Linux File Permissions, Groups, and Users originally appeared on Yet Another Linux Blog on November 3, 2010.

Then the worst thing that could possibly happen on my Gateway M250 happened…ALSA stopped working and there was no sound.  I started pulseaudio back up to no avail…no matter what I did, nothing worked to get sound up and running.

It was about the time I wanted to carve the sound pieces out of my laptop and throw them across the room that I decided to give everything I tried in the past one more try.

I fixed it…and I was pretty amazed that the solution was as easy as it was having spent weeks upon weeks fighting the pulseaudio issue.  I can only surmise that I made a typo in the module that I needed to blacklist.  After this arduous journey, it came down to blacklisting the modem sound card to make things work.

To do this on Mandriva and Unity Linux you’ll need to blacklist the following module:  snd_intel8x0m.  Notice the ‘m’ on the end of the standard module snd_intel8x0 for the ICH6 sound card.

You can do this by editing the following file as root in your favorite text editor:  /etc/modprobe.d/blacklist-compat

Add the following line anywhere in this file:

blacklist snd_intel8x0m

After that, you can reboot to make sure the module is blacklisted.  I know there are more elegant ways to load and unload kernel modules but this is the easiest way to get the job done for new users.  Subsequent reboots resulted in still having sounds.  Thankfully, I didn’t have to rip my laptop apart in a quest to throw the sound portions.  I sure hope this helps others out!

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ICH6 Intel Sound on Unity or Mandriva PulseAudio Fix originally appeared on Yet Another Linux Blog on October 22, 2010.

smart install flash-player-plugin

Next, we need to create a directory under your profile to house the flashplayer plugin and then copy it there.  I’m sure we might be able to get by with a symbolic link but I didn’t try that out…

mkdir -p ~/.mozilla/plugins && cp /usr/lib/mozilla/plugins/libflashplayer.so ~/.mozilla/plugins/

That’s it, it should work now.  I’ve done this on 32bit Unity Linux 2010.1 on a Gateway M250.  Hopefully this helps out someone out there

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Midori, Flash, and Unity Linux 2010 originally appeared on Yet Another Linux Blog on September 8, 2010.

find / -name 'pattern'

Really though, the power of find isn’t just in finding names of files but rather specific details about those files. For example, if you wanted to find files which are writable by both their owner and their group:

find / -perm -444 -perm /222 ! -perm /111

or perhaps find any file that’s been altered in your Download directory in the past 24 hours:

find /home/user/Downloads/ -mtime 0

As you can see, the find command is very versatile and can be used to find an array of different attributes of files.  There are times though where I’m just looking for something and I don’t want to have to wait for the command to scan the entire directory tree in order to track it down.  That’s where locate comes in with quick and simple results.

Using the Locate Command

Using the locate command can only be accomplished if you install the mlocate package.  Most major distributions have this available.  If not, head over to the mlocate homepage and install manually.  Once that is accomplished, you’ll need to manually run a command to index your filesystem with it…otherwise, you’ll have to wait for the command to run automatically as it registers with cron to do so on a system level.  Open an terminal and change to your root user, then execute the following:

updatedb &

This updates the mlocate database that indexes your files and forks it to the background (the ‘&’ forks it to the background).  You can now logout of the terminal as root and the process will quietly work in the background.

After the command completes, using mlocate is as easy as using the locate command:

locate firefox | less

The command above will look for all files with firefox in the name and pipe the command through less so you can use the spacebar or enter key to scroll the file buffer.  Of course, the reason we pipe it through less is because any file that resides in the ‘firefox’ directory will be reported in the output.  While this tool isn’t as granular as the find command, it is a quick way to track down paths, directories, and files you know should exist.  Since the data is indexed using the updatedb command (by cron) the results are very quick and the command does not have to scan through the filesystem to return the results.

There are plenty more advanced options via flags (such as following symbolic links, making search term case sensitive, and even using regexp).  See the man page for details on how each of these options work.  Play around with locate and see what you can do!  It’s a powerful and quick search command!

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Finding Files with locate originally appeared on Yet Another Linux Blog on September 7, 2010.

What is Openbox?

From the Openbox homepage, “Openbox is a minimalistic, highly configurable, next generation window manager with extensive standards support.”  From using it, I often think of it as fluxbox-like with the benefits of being able to dip into Gnome or KDE for the items that I want to use.  Your desktop will then run with speed and simplicity using only the elements you want to use with it.

So…Let’s get Started…

This How-To will assume that you’re running Foresight Linux, you’re logged into Gnome and that you’re familiar with conary, the package manager for Foresight.  First and foremost, install openbox:

[devnet@lostlap Desktop]$ sudo conary update openbox obmenu obconf

This installs the needed components to run Openbox on your system. Openbox is minimal by default though so if you login to the environment now for the first time, there will be no taskbars, nothing…just a large blank area for you to work with. We will need to install some extra components to give a bit more functionality. If you’d like a panel menu, I recommend using tint2. I used to use pypanel which is a small panel written in python but this panel is no longer developed.

There are other panels that are packaged with openbox in mind for Foresight; fbpanel is available, which is a very fast and functional menu bar. I like lxpanel also, which is fbpanel with some easier configuration options. For a full list, please see openbox documentation. For our purposes here, we will install tint2:

[devnet@lostlap Desktop]$ sudo conary update tint2

Now we need to copy the default configuration file for tint2 so we can build our panel to our liking.  You’ll have to create the default path for the tint2rc configuration file.  To do this and copy the config file:

[devnet@lostlap Desktop]$ mkdir -p ~/.config/tint2/
[devnet@lostlap Desktop]$ cp /etc/xdg/tint2/tint2rc ~/.config/tint2/

Now tint2 has a configuration file in place and is ready for Openbox to start.

Let the Configuration Begin!

The hard part (install) is now out of the way thanks to the conary package manager. Now we need to configure Openbox so that it’s ready for us when we log out of Gnome. The configuration files will need to be copied to /home/user/.config/openbox.  Of course, this path doesn’t exist yet so we’ll need to create it like this:

[devnet@lostlap Desktop]$ mkdir -p ~/.config/openbox/

Visiting there now will show that there aren’t any files in this directory.  The file we’ll absolutely need to place there is autostart.sh. Other files that will be in here are rc.xml which is for obconf (openbox configuration) and menu.xml (openbox menu system).  We’ll copy menu.xml from a default copy there later.  The other file should auto-create when loading for the first time (rc.xml)

The autostart.sh file is what starts all of our services and our tint2 panel we just installed as well as setup our wallpaper and other items.  Instead of going through the options you can place in here, I’m going to share my autostart.sh to get you up and running quickly.  Please note that if you chose not to install fbpanel and use the gnome-panel or other panel instead, you’ll need to comment the pypanel line below and uncomment what you’ll be using:

[devnet@lostlap Desktop]$  cat autostart.sh
# This shell script is run before Openbox launches.
# Environment variables set here are passed to the Openbox session.
##############################################################
# Panel Section
##############################################################
# pypanel, my favorite panel for openbox
#(sleep 3 && pypanel) &
# Use the wbar Launcher if you would like.  Don't forget to install it before uncommenting
# wbar &
(sleep 3 && tint2) &

#############################################################
# Gnome Integration Section
#############################################################
# This section let's Gnome give us some of its desktopiness
gnome-power-manager &
nm-applet --sm-disable &
/usr/libexec/gnome-settings-daemon &
gnome-volume-manager --sm-disable &
gnome-keyring-daemon &

###########################################################
# Other Add-on's for Openbox
###########################################################
# Make your wallpaper restore to last setting using Nitrogen.
nitrogen --restore &
parcellite &
volumeicon &
################################# End ###################

Download my autostart.sh

To create the menu system file for openbox, we’ll copy from the default installation to our .config/openbox directory (so we can use obmenu…otherwise, that command will give us an error) so use the following command in a terminal:

[devnet@lostlap Desktop]$ cp /etc/xdg/openbox/menu.xml ~/.config/openbox/

Now you’re ready to login and reap what you have sown Logout of Gnome and change sessions in GDM to Openbox.  Notice that your tint2 panel starts up and has the gnome applications we recorded in the autostart.sh file above running and docked! You can add more options to your autostart.sh file and you can also edit tint2rc (in your /home/user/.config/tint2 directory) to store settings for your panel.

I’ve Installed and am Running, Now What?

Now you get to customize the Openbox menu with your favorite applications. Menus are activated by right clicking anywhere on the desktop. There are a few default applications…I choose obconf right away so that I can choose a theme I like and increase the text size since I’m using a high resolution. After that is done, I right click for the menu again and go to applications >> xterm. When the terminal pops up, I type obmenu. From there, I’ll be able to edit my right click menu.

Now instead of entering obmenu in a terminal each time, let’s add it to our right click options. In the obmenu window that you opened in the last paragraph, expand the Openbox 3 option. Find obconf and highlight it. Click ‘new item’ and add obmenu for a label, execute for action, and obmenu for Execute. This will add obmenu to your right click options so you don’t have to open a terminal each time to do things. You can also customize any of the items you find in applications…I put a few things I normally need such as thunderbird, firefox, gnome-terminal, etc. Feel free to add whatever you need…you can have many submenu’s . It’s setup is pretty straightforward.

Nitrogen, the wallpaper manager, requires a small tweak as well to get working. What I did was create a /home/username/Photos/Wallpaper directory and then loaded it up with my favorite desktop wallpaper. Good places to go for cool wallpapers are desktopography.com and vladstudio.com.  Next, install Nitrogen:

[devnet@lostlap Desktop]$ sudo conary update Nitrogen

After your first login, you’ll need to add a menu entry using obmenu to call the nitrogen browser. So create the menu entry and the action you call is:

nitrogen /home/username/Photos/wallpaper

Of course, replace ‘username’ with your users name.  This will allow you to open up all the wallpaper photos inside of that directory.

So What Have we Done?

Today, we’ve installed Openbox on Foresight Linux. We’ve given it a tint2 panel so we have a place to dock applications and we’ve customized the Openbox right click menu and added a wallpaper program called Nitrogen. Hopefully, this shows you the customizable features of Openbox and also shows you the speed that Openbox operates at. It’s a very minimalistic environment, yet one that can be very powerful.

Installation Notes of Interest

tint2

Tint2 is my newly crowned favorite panel for openbox.  It’s lightweight and is able to be configured in so many ways.  I added the sleep command inside my autostart.sh to make sure that the desktop is loaded before the tint2 panel tries to load…mostly, this is due to network manager wanting to animate while the panel loads.  This isn’t as much problem with tint2 as it is with pypanel (see below).

pypanel

Some things I’ve noticed when running openbox…network manager has problems with pypanel. I added the sleep command inside my autostart.sh and this is much better now…but there may be similar problems with network manager. It’s really NM searching for a network and it causes the panel to flicker a bit. Not a real show stopper.

Gnome-panel

Gnome-panel running inside openbox causes a few errors to pop up when I login. This could be due to the fact that I’ve started things in my autostart.sh out of order…I’m also not all together sure what is causing these errors. The problem seems to be with the docking area of gnome-panel as when I minimize programs they are not docked. Easily fixable, but annoying nonetheless.

Alternative Panels

There are quite a few alternative panels out there.  Fbpanel is one.  Perlpanel is another.  Fbpanel and lxpanel are available in the Foresight repositories. You can also add other launchers like wbar if you so desire.

Screenshot

Openbox on Foresight

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Installing Openbox on Foresight Linux originally appeared on Yet Another Linux Blog on May 30, 2010.