Programming :: Methods For Extracting Data Strings From Output Files?

I am trying to develop a method of reading files generated by other programs. I am trying to find the most versatile approach. I have been trying bash, and have been making good progress with sed, however I was wondering if there was a "standard" approach to this sort of thing. The main features I would like to implement concern reading finding strings based on various forms of context and storing them to variables and/or arrays. Here are the most general tasks:

a) Read the first word(or floating point) that comes after a given string (solved in another thread)

b) Read the nth line after a given string

c) Read all text between two given strings

d) Save the output of task a), task b) or task c) (above) into an array if the "given string(s)" is/are not unique.

e)Read text between two non-unique strings i.e. text between the nth occurrence of string1 and the mth occurrence of string2

As far as I can tell, those five scripts should be able to parse just about any text pattern. I am by no means fluent in these languages. But I could use a starting point. My main concern is speed. I intend to use these scripts in a program that reads and writes hundreds of input and output files--each with a different value of some parameter(s).

The files will most likely be no more than a few dozen lines, but I can think of some applications that could generate a few hundred lines. I have the input file generator down pretty well. Parsing the output is quite a bit trickier. And, of course, the option for parallelization will be very desirable for many practical applications.