need clarification on relations on input and output strings separated by operators. liken it to learning basic grammar rules of a new language to enable one to move forward.

What language are you talking about?

the things I read about bash on the books were mostly about parsing string. So please base your reply on BASH. Thank you for enlightening people like me!

Your question is very vague and hard to understand. If you have a specific example of what you want to do, please post it.

In general, Bash and other shells work by storing strings in variables, manipulating the contents in various ways, and then echoing them back out in your desired format. There are a large number of techniques available for doing all of these steps, and what to use depends on exactly what you need to do.

string manipulation


The nearest I can guess from your post is that possibly you want to break up a line/string based on some delimiter? If so, this is probably best done by reading the line into an array, using the IFS variable (or a similar delimiting function, depending on the technique used) to specify the character used for dividing the fields.

http://mywiki.wooledge.org/BashGuide/Arrays
http://mywiki.wooledge.org/BashFAQ/005

I also suggest reading through the bash guide here to get a better grasp on the basic scripting concepts.

http://mywiki.wooledge.org/BashGuide