Multiple monitors with i3 wm

 This took a very long time to happen. Ultimately it is a downgrade which has made me to take up multiple monitor setup. A Dell laptop, around 5 years old, was discarded by my son certifying it to be very slow. However, the laptop was upto the task considering the mac mini which I had. So, upgraded the hdd to ssd. I started from a clean slate. Installed a clean copy of windog 10(well, paid for the license when the laptop was brought). After a flurry of updates and reboots... phew.. it was complete.

Now to the favorite part. Getting Arch Gnu/Lnux onto the laptop. Tried installing arch based derivatives with i3 as the wm. However, was not happy with the plethora of packages which got installed. I have nothing against the distros. However, I have been destroyed by the plain/vanilla install of arch Gnu/Linux on all my computers. So wiped again, and did a vanilla arch gnu/linux install. Installing packages as and when I was hitting a wall for a particular task. Just goes a long way to tell how much effort you have put to make your arch gnu/linux install "your own". That is not time wasted. But, time well spent.

As I again, brought the install to my liking, it is bewildering to see the control one has on his computer. Compare it with the windows install. Cannot compare. Yes, cannot compare the ease with which GBs of software lands on your computer in the name of "ease of use". Well, Freedom is never easy and never will be. 

 However, the point of the post is multiple monitor setup with i3. Let me start by telling that it was not easy. Lot of web searching and personal shares of various users have made me to nearly approach the setup which I liked. Again, which I liked... so... The basic premise is I wanted 05 workspaces on the QHD monitor and another 05 workspaces on the laptop display(FHD). This was my requirement. However, wherever, I was searching, the majority of the results concentrated on moving workspaces or containers or windows or another atomic elements in i3. I did not want to move applications between the monitors. Some apps are better on QHD and some on FHD. So the applications will go respectively to those workspaces as decided by the user(me). Tie the workspaces to the monitors

Howver, the point of the post is multiple monitor setup with i3. Let me start by telling that it was not easy. Lot of web searching and personal shares of various users have made me to nearly approach the setup which I liked. Again, which I liked... so...

The basic premise is I wanted 05 workspaces on the QHD monitor and another 05 workspaces on the laptop display(FHD). This was my requirement. However, wherever, I was searching, the onus was on moving workspaces or containers or windows or another atomic element in i3. I did not want to move applications between the monitors. Some apps are better on QHD and some on FHD. So the applications will go respectively to those workspaces as decided by the user(me).

Tie the workspaces to the monitors

workspace $ws1 output $qhd
workspace $ws2 output $qhd
workspace $ws3 output $qhd
workspace $ws4 output $qhd
workspace $ws5 output $qhd
workspace $ws6 output $fhd
workspace $ws7 output $fhd
workspace $ws8 output $fhd
workspace $ws9 output $fhd
workspace $ws10 output $fhd

Added the following to meet the requirement which I set out to achieve. When you now hit the hot key for navigating to a particular workspace, irrespective of the monitor, the focus is on that particular workspace.

bindsym $mod+1 focus output $qhd;workspace $ws1
bindsym $mod+2 focus output $qhd;workspace $ws2
bindsym $mod+3 focus output $qhd;workspace $ws3
bindsym $mod+4 focus output $qhd;workspace $ws4
bindsym $mod+5 focus output $qhd;workspace $ws5
bindsym $mod+6 focus output $fhd;workspace $ws8
bindsym $mod+7 focus output $fhd;workspace $ws7
bindsym $mod+8 focus output $fhd;workspace $ws8
bindsym $mod+9 focus output $fhd;workspace $ws9
bindsym $mod+0 focus output $fhd;workspace $ws10

As a bonus, now, let us say you have the workspace you want to work on in clear view on the other monitor. You just want focus on that monitor. Add the following to your config

bindsym $mod+period focus output left

Kindly bear in mind, the keybindings which are already utilized in your config file before changing anything.

Thats it.

A big Shout-out and Thanks to all the devs and users making the "free as in freedom" world possible.

xargs - The generic tool for arguments

    xargs is one of the most versatile tool used by command line warriors. There is a sort of aura around this command. Numerous videos are out there explaining the usage of this tool. The discussions below are to be taken as one for the entry level command line users. Kindly refer to the man pages for further advanced usage. In particular more information and its usage can be better appreciated from books and articles on shell programming, where a discussion on this is a mainstay.

    I will be using music files and c source files as examples wherever appropriate according to the easiness with which the underlying usage of xargs is more clear.

In the present directory as we start this discussion, we have the following files

music1.mp3
music2.mp3
music 3.mp3(notice the space in between music and 3)
music 4.mp3
big_program1.c
big_program2.c
big_program3.c

ls *.mp3 | xargs -t

echo music1.mp3 music2.mp3 music 3.mp3 music 4.mp3
music1.mp3 music2.mp3 music 3.mp3 music 4.mp3

    The output above is a little cryptic. Let us clear it first. If there is no other command to which xargs passes the arguments, the by default xargs pipes it to echo. The -t option is same as --verbose option with GNU extensions(by the way, I like GNU extensions for any program, they are more verbose and use the long form to extend  and explain what that particular option would do). By specifying the -t option, we are telling xargs to be more verbose in its activities. The result was that the xargs command took the output of ls and piped it to echo. We can see that exact executed by xargs in the first line of the output. The total result of the command is the output in the second line. All the arguments were passed on at once to the echo command.

    Now, let us change the above command such that the echo command is run on every argument. For that,

ls *.mp3 | xargs -t -n 1

echo music1.mp3
music1.mp3
echo music2.mp3
music2.mp3
echo music
music
echo 3.mp3
3.mp3
echo music
music
echo 4.mp3
4.mp3

    If we see the output, we met our task, partially. echo command is run on every argument. However, the file names with spaces in them have created a problem. By default, the delimiter for xargs is the space/blank character. To ensure that the above command works properly, we have to include the information of the delimiter in the xargs command, like so.


ls *.mp3 | xargs -t -n 1 -d'\n'

echo music1.mp3
music1.mp3
echo music2.mp3
music2.mp3
echo 'music 3.mp3'
music 3.mp3
echo 'music 4.mp3'
music 4.mp3

    Now, we see that the xargs command met our requirements. Now we are pretty confident that we can now pass on these xargs to other programs and are confident of them working properly. Let us now play the mp3s.


ls *.mp3 | xargs -t -n 1 -d'\n' mpg123

    This will now play all the mp3 files in alphanumeric order as listed by the default ls command, one after the another.

    Let us now take up the next key strength of xargs. xargs has the capability to spawn multiple processes so that arguments can be passed on to multiple instances of the program. For eg,

ls *.mp3 | xargs -t -n 1 -d'\n' -P 8 mpg123

    That was indeed funny, right. Seriously, that is a very wrong example to illustrate the parallel processing achieved by the above command. The above command starts multiple instances of mpg123, with all the instance playing an argument supplied. You can increase the argument for -P based on the number of files piped into the final command. Here you have all the four songs playing in parallel. The sound output might be interesting for music producers. For us listeners, nothing.

    Let us now consider a proper, practical example for this spawning of multiple processes,

ls *.c | xargs -t -n 1 -P 8 gcc

    The above command will run multiple instances of gcc at the same time and the compilation will happen in parallel on all the 3 files in the present directory. To do this kindly ensure that your programs can be compiled so and are stand alone and not dependent on each other being compiled already. Here we do not have the problem of file name containing spaces. If you are comfortable with

make -j 8

    For compiling your linux kernel, you know exactly what is happening here. The linux kernel is one of the greatest and practical examples for compiling sources in parallel. What a great feat. Kudos to all the kernel devs.

    With this, we come to the end of this gentle introduction to one of the most important tools for shell programming. The knowledge of xargs is a must for all shell programming aficionados.

    The standard thanks and regards to all the FLOSS users and devs. You people are great. Thanks again.