A BAT file is a DOS batch file used to execute commands with the Windows Command Prompt (cmd.exe). It contains a series of line commands in plain text that are executed to perform various tasks, such as starting programs or running maintenance utilities within Windows.

BAT files are typically only used by computer-savvy DOS or Windows users looking to make repetitive tasks easier to complete. Users can manually create BAT files with a text editor, such as Notepad or Wordpad, and add multiple commands on separate lines that can be executed by the command-line interpreter. When saving a batch file, save it with a .bat extension or save it as a .TXT file then rename the .txt file extension as .bat.