Windows batch files: .bat vs .cmd?

Question

As I understand it, .bat is the old 16-bit naming convention, and .cmd is for 32-bit Windows, i.e., starting with NT. But I continue to see .bat fi

Answer 1

The extension makes no difference.

There are slight differences between COMMAND.COM handling the file vs CMD.EXE.

Answer 2

Since the original post was regarding the consequences of using the .bat or .cmd suffix, not necessarily the commands inside the file...

One other difference between .bat and .cmd is that if two files exist with the same file name and both those extensions, then:

• entering filename or filename.bat at the command line will run the .bat file

• to run the .cmd file, you have to enter filename.cmd

Answer 3

Slightly off topic, but have you considered Windows Scripting Host? You might find it nicer.

Answer 4

No - it doesn't matter in the slightest. On NT the .bat and .cmd extension both cause the cmd.exe processor to process the file in exactly the same way.

Additional interesting information about command.com vs. cmd.exe on WinNT-class systems from MS TechNet (http://technet.microsoft.com/en-us/library/cc723564.aspx):

This behavior reveals a quite subtle feature of Windows NT that is very important. The 16-bit MS-DOS shell (COMMAND.COM) that ships with Windows NT is specially designed for Windows NT. When a command is entered for execution by this shell, it does not actually execute it. Instead, it packages the command text and sends it to a 32-bit CMD.EXE command shell for execution. Because all commands are actually executed by CMD.EXE (the Windows NT command shell), the 16-bit shell inherits all the features and facilities of the full Windows NT shell.

Answer 5

a difference:

.cmd files are loaded into memory before being executed. .bat files execute a line, read the next line, execute that line...

you can come across this when you execute a script file and then edit it before it's done executing. bat files will be messed up by this, but cmd files won't.

Answer 6

From this news group posting by Mark Zbikowski himself:

The differences between .CMD and .BAT as far as CMD.EXE is concerned are: With extensions enabled, PATH/APPEND/PROMPT/SET/ASSOC in .CMD files will set ERRORLEVEL regardless of error. .BAT sets ERRORLEVEL only on errors.

In other words, if ERRORLEVEL is set to non-0 and then you run one of those commands, the resulting ERRORLEVEL will be:

• left alone at its non-0 value in a .bat file
• reset to 0 in a .cmd file.