A batch process performs a list of commands in sequence. It be run by a computer's operating system using a script or batch file, or may be executed within a program using a macro or internal scripting tool. For example, an accountant may create a script to open several financial programs at once, saving him the hassle of opening each program individually. This type of batch process would be executed by the operating system, such as Windows or the Mac OS. A Photoshop user, on the other hand, might use a batch process to modify several images at one time. For example, she might record an action within Photoshop that resizes and crops an image. Once the action has been recorded, she can batch process a folder of images, which will perform the action on all the images in the folder.
Batch processing can save time and energy by automating repetitive tasks. While it may take awhile to write the script or record the repetitive actions, doing it once is certainly better than having to do it many times.