Change a line in over 1300+ files

can anyone provide any assistance on how to change a line of code (in over 1300+ files) in one shot?

I have 1300+ files, each has a line such as: <form … action=“test.php”>

I need to change all 1300+ files to: <form … action=“another.php”>

Any thoughts?
I’ve heard that there are methods on a Linux system to find and replace a string in a batch of files…any truth to this? and if so, any assistance?

Thanks!