Shell Programming and Scripting

For the data shown in red, do you want your script to perform the arithmetic calculations shown in the comments, or do you want the comments to be part of the output with the numeric values shown replaced with data from your input file?

If your script is supposed to perform the calculations:

Thanks for the reply Don Cragun,

1. First of all I have posted only a portion or my code which requires data from file1 to file2 and level0 is the pre-defined integer value in my case. I have to enter some value.

2. I need arbitrary precision because precision plays a very important role in my subject.

3. I can change the input and output cases alike. Its really not matters.

4. No I want xg with xMin and xMax in this way only. Its part of calculation. Not a comment.

5. I am using bash shell environment


Thanks & Regards,
linuxUser_

First, you have not answered Robin's question: Is this homework? If it isn't homework, where is this data coming from and how will the output be used? Without an answer to these questions, this thread will be closed.

Then, more questions based on your responses above:
1. No, you have not shown us any of your code (except for a sed command I gave you which seems to have no use in this thread, and a grep that gives you output you don't know how to process. I agree with Robin, we need to see the code you have written (even if it isn't working). And, we need to see a more representative sample of the input files this script is supposed to process. Searching for text matching a pattern in a file of arbitrarily formatted data is somewhere between hard and impossible. Searching for text in a text file where the format of all of the data in the file is well described is somewhere between easy and trivial. Make all of our lives easier by describing you input files fully.

Your first post said in file1 I have something like this

Code:

Min X = -250.000000, Max X =  250.000000
Min Y = -95.000000, Max Y =  95.000000
Min Z = -95.000000, Max Z =  136.500000

The following is something like that:

Code:

MinX = -250.000000,MaxX =  250.000000
Min y=-95.000000, Max Y =95.000000
miNz=-95.000000,maxZ=136.500000

but writing REs that recognize "something like" both of these is a much, much, more difficult task than writing an RE to match something that is "exactly" like the the first format. Are min values always negative? Are max values always non-negative? Are max values always positive?

If level0 is a "pre-defined integer value", why do you "have to enter some value"? Please explain.

2. What are you doing where getting 13 or more significant digits in the results from calculating a quotient from the sum of two input values divided by a third integer is insufficient? We can calculate arbitrary (but specified) precision results using bc or dc, but we can't print arbitrary (unspecified) precision output. (If xMin is -1, xMax is 1, and level0 is 3, your script will spend the rest of our lives printing an unending number if you insist on arbitrary precision output.) You need to clearly specify what ranges of values x, y, z, and level0 can take; and for some representative real values of those variables, show us the exact output that should be produced (not comments saying calculations should be performed) AND don't choose "nice" numbers that will produce integral results; show us real world values demonstrating the precision you need in your output. And, give a clear English description of how the precision is to be determined.

3. Maybe case doesn't matter to you, but we need to know if your script has to perform case insensitive searches for your variables in your input file and if it has to perform case translations to get the required output. We need a clear specification of what is in your input files and exactly what you want in your output file to help you write code that can find what you want in your input files and produce what you want in your output files.

4. This doesn't address the question I asked. Can the output be:

Code:

xMin -250.000000;
xMax 250.000000;
xg  result from calculating abs((250.000000-(-250.000000))/$level0);

yMin -95.000000;
yMax 95.000000;
yg  result from calculating abs((95.000000-(-95.000000))/$level0);

zMin -95.000000;
zMax 136.500000;
zg  result from calculating abs((136.500000-(-95.000000))/$level0)";

instead of the order you said you want. It will simplify your code if we can produce the x related results when we find the input line:

Code:

Min X = -250.000000, Max X =  250.000000

instead of having to save data to print at the end after finding all three significant input lines.

5. That didn't answer the question, but since you need more precision that C double-precision computation provide, it probably doesn't matter. Also, what OS are you using for this project?

And, just for fun, why is speed so important in calculating three values? Are there hundreds of input files to process? Is it the calculations that have to be fast? Or is it searching HUGE input files for your three important data lines that has to be fast? In most projects I've worked on, the speed of this part of a larger project would be insignificant unless we did some really gross stuff to slow it down unless this code will be in a loop processing lots of files.

Dear Don Cragun,

It is not home work. I am developing a tool. It requires some automation. For automating I am using shell scripting for now.

file1 addresses the output form one of my c++ code.
file2 is part of code for another software which requires date in that format.

All I need is copying a text file and paste required values to other file in the format I specified.

1. form your questions and inputs I decides to write file1 as

Code:

minX = -250.000000;
maxX =  250.000000; minY = -95.000000;
maxY = 95.000000; minZ = -95.000000;
maxZ = 136.500000;

I guess it should be easy now to read the data?

2. Regarding precision:
All I need is a shell script that can successfully copy a number like 10.123456 or 10.12345678, it should exactly copy the number.
This plays a little important role in my application.

3. using

Code:

-i

in shell scripts is case insensitive search right? Yea your are right case really not matters.

4. Both are same. I mean it can be

Code:

 xg  #calc "abs((250.000000-(-250.000000))/$level0)";

or

Code:

xg  value;

But I would like to get 1st if it is really not difficult.

5. Linux 12.04LTS


Where speed came into picture? If ever I said speed in my previous posts, It must be related to urgency in finishing this task.
I have to copy only one file so speed really not matters.

Thanks & Regards
linuxUser_

Dear Don Cragun & rbatte1,

I have solved the issue. Thanks for help .

Regards,
linuxUser_

Solved it how?

Dear Corona,

I taught I dont have enough time to write program in c++ but finally decided to write in cpp only. Just because of time constrains I have chosen shell, but my knowledge in shell is completely below basic.
Any way I really like this forum. People here are really helpful.
I will try to learn shell scripting also asap

Thanks & Regards,
linuxUser_