Shell Programming and Scripting

Hopefully someone can help out here. This is probably fairly basic, but I've searched and tried several variations of the solutions presented in these forums, so I'll go ahead and ask.

How can I locate a string in a file, delete the characters after the string and then replace the string with a new string?

Currently I have this, which is getting me close to a solution, but I can't get the extra characters removed:

for file in test_program; do

sed 's/OUTPUT='/'OUTPUT='$file/g $file > new_$file

done

Here is the test_program file that I am testing with:

This is a test
This is a test
/OUTPUT=("This is a test")
This is a test

Here are the results after running my script:

This is a test
This is a test
/OUTPUT=test_program("This is a test")
This is a test

I just need to have the script get rid of ("This is a test") and it will work fine for what I am trying to do, which is make this change to several thousand files at one time. Any assistance would be appreciated. I've got other ways to do this, but now that I've embarked down the Unix path, I want to see how this is done.

try:
sed 's/OUTPUT=.*/OUTPUT='$file'/' $file > new_$file

Thank you!! That did the trick. I had already tried with the asterisk, but I left out the period.