What is a .bat file and is it safe to open?

A .bat file, short for "batch file," is a plain text script used on Windows operating systems. It contains a sequence of commands that the Windows Command Prompt (cmd.exe) can execute automatically when the file is opened. Unlike a standard program (.exe file) compiled into machine code, a .bat file is human-readable and interpreted line-by-line. However, this direct execution of commands also means opening an untrusted .bat file can be risky.

Common practical uses include automating repetitive or complex tasks. For example, a .bat file might start several applications at once for a user or automate file backups and software installations across multiple computers within an organization's IT environment. System administrators heavily utilize batch scripts for managing networks and user accounts due to their simplicity and direct access to system commands.

The main advantage of .bat files is their simplicity for automating tasks without complex programming. They are lightweight and universally understood by all Windows versions. However, their major limitation is the lack of robust scripting features compared to PowerShell or Python. Critically, .bat files pose significant security risks because they run with the permissions of the user who opens them and can execute harmful commands silently. Malware frequently uses .bat files. Therefore, it is essential to only open .bat files received from trusted sources and understand their contents. Always exercise caution.