steam-shell: Two processes in one terminal

Community bonding period turned out to be quite fruitful I got to know my community really well and not only that I also solved quite a number of issues which helped me understand the code base. Daily scrum meetings played a very important role in making us work professionally and cover some substantial work. Official coding period began on 23rd May and I was all set for the challenges and the sleepless nights to come. Here I will be discussing the tasks I covered in my first week.

As suggested by my mentors I had changed my plans a bit by moving the work on edit command before implementing the TLS layer on COAL. I started small by fixing the edit command. The edit command opens the specified file in vi/vim/emac. In vi and vim the editor was misbehaving and not letting us work on the file. I took up this as my first task for Google Summer of Code 2016. This helped me understand steam-shell and applauncher, which is used to load the editor, in detail. Vi and vim editors have an advantage of letting the user edit the file in the same terminal window.

Looking at the issue itself it was not possible to do any kind of backtracking. The vi editor was just throwing rubbish on the screen when the user attempted to type anything.

overlapping process
vi editor showing the garbage and the steam-shell command

At first I was under the impression that it was a problem with the editor itself. I even tried approaching the vi.stackexchange.com , where the vi developers could help me. However all this was in vain. After a lot more forensics and re-reading the code multiple number of times I realized two process were active and sharing the same terminal space. How did I come to this conclusion? Well it was a very minute detail that I noticed. While in the vi editor window, with the document open and the editor throwing garbage at you when you press the up arrow the editor clears some area and show the commands executed on the steam-shell. This can be seen in the above image

This simply meant that both the process for steam-shell and the vi editor was running and sharing the same terminal space. The solution was quite simple. Just called editor→wait() to suspend the calling the process till the called process was over.

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