# Writing a script to repeat a C program (Umbrella Sampling Script)

1. Mar 7, 2013

### kd215

I have a C code that creates a small histogram, but I need it to rerun many many times by changing one variable that the user can input. I've NEVER used C until this week so if someone could given me an idea of how to write a script to repeat a code and save a bunch of data from it that would be great!

Thanks!

2. Mar 7, 2013

### rcgldr

It's not clear to me what you want to do. You could create a script / batch file to run the program repeatedly, or you could change the program so that it loops and creates many historgrams.

3. Mar 7, 2013

### kd215

I don't even know the basics of writing a script. I'm really confused with the syntax. Are there any references for basic C programming that you know of?

4. Mar 7, 2013

### Staff: Mentor

Sounds like your problem is not with C but with programming in general.

5. Mar 7, 2013

### rcgldr

What operating sytem are you using? If it's windows, then you'll be using MSDOS type batch files, which include a loop operator. If it's unix or linux, there are different command "shells", each with it's own scripting language (although they are similar).

I haven't kept up with the books or articles that are available. You could do a web search for "C primer", or perhaps get a text book used for a local college class. Hopefully someone here at PF can recommend a book.

6. Mar 7, 2013

### Timo

Assuming you use Linux, copy the following lines into a file and make it executable (chmod u+x <filename>):
Code (Text):

#!/bin/bash
for parameter in 0.1 0.2 0.3 ; do
echo "calling the program with the parameter "$parameter # call the program. ./my_program$parameter

# backup the result to some other file.
cp theresultfile resultfile_of_parameter_\$parameter
done

Customization to your needs should be straightforward - Windows scripts should be somewhat similar.