Question

Essentially I am looking to write a shell script, likely using a for loop, that would allow me to repeat a program call multiple times without having to do it by hand (I don’t know exactly how to explain this, but i want to perform the java TestFile.java command in the cmd window multiple times without doing it by hand).

I am trying to write it for the UNIX shell in bash, if that helps at all.

My program outputs a set of numbers that I want to look at to analyze end behavior, so I need to perform many tests for many different inputs and I want to streamline the process. I have a pretty basic understanding of shell scripting – i tried to teach myself today but I couldn’t really understand the syntax of the for loop or the syntax of how to write a .java file call, but I would be able to write them in shell script with a little help.

Answer 1

This will do:

#!/bin/bash

javac Testfile.java # compile the program

for((i=1;i<=50;i++))
do
echo "Output of Iteration $i" >> outfile
java Testfile >> outfile
done

This will compile your java program and run it for 50 times and store the output in a file named outfile. Likewise, you can change the 50 for the number of iterations you want.