How to format date for file content using linux command line tools? 

Input:
aaa;1.70;ccc;20.01.13;zz;2013;
uuu;2.70;lll;17.12.10;zz;2013;
fff;3.70;nnn;31.01.98;zz;2013;
auu;8.70;nuu;30.02.96;zz;2013;

Output:
aaa;1.70;ccc;20.01.2013;zz;2013;
uuu;2.70;lll;17.12.2010;zz;2013;
fff;3.70;nnn;31;01.1998;zz;2013;
auu;8.70;nuu;30.02.1996;zz;2013;


Question: Who should pursue a Ph.D degree?
Answer: Among the people who should pursue a PhD degree are the ones who can write:


  My life-goal is being a professor. And I love to do research. 


This is the number one reason to get into grad school. However, it's not clear at this point that you have an accurate idea of what it means, on a daily basis, to work in research.

Sure there are fun times fiddling with the knobs of expensive equipment, drawing equations on napkins until late in the night, traveling to exotic conference locations like Baltimore, etc. There are also these brief moments when you feel like an undergrad actually learned something from you, and those where you share inside jokes that you can tell for sure only your advisor and yourself can understand. I recall a quote from a senior researcher in my field saying "Can you believe that they pay us to do what we love?".

But there are other aspects that are less glamorous. Administrative work, data bookkeeping, actual bookkeeping, wondering what you will do with your life, filing grant applications, etc. There is the anguish about funding, the frustration of aborted projects, the time and energy wasted in dealing with department politics.

And there is teaching which can be both a joy and a pain in the neck.


  My BSc. GPA was 2.84/4.00 but finished my MSc. with 3.50/4.00


I don't know what GPA is, nor how to interpret your grade, but the context tells me that you think they could be better. Passing exams and conducting research are different jobs, not being excellent at one does not mean you can't be good at the second one (a) although it often helps; b) the reverse is also true). It will make things harder for you when applying to grad school, but after that it becomes irrelevant. What matters more is what you actually learned, some people have ok grades but understood a great deal of the concepts.


  I let go of my work and absorbed in other stuff


That you will have to work on. There is an infinite number of things that you can do but work on your research. Nobody will force you to do it since pretty much the only one who will suffer from your procrastination will be you. The good news (sort of) is that you are not alone...


  What kind of skills/characteristics do you look for a potential
  academician?


There are many, and most of them overlap with what it needs to achieve a successful career in the industry. But I don't know any successful researcher who is not thorough. Being creative sure is necessary, but it's the easiest part. What will make you stand out is when you can discipline yourself into rigorously testing them.

It also help if you know how to sell your ideas. Researchers hate to admit it but a significant factor in their success relates to how well they can convey a message. (Note that bad communication is an indicator of bad science, but it gives a lot of false positive).