and (cmd)?= processing.
These features of DOS 6.0+ provide interactive control over execution of
individual CONFIG.SYS commands.  DOS 6.2: Ctrl+F8 lets you control
execution of individual commands in AUTOEXEC.BAT.

During the System Startup Sequence, the message...

Starting MS-DOS...

...appears and the system pauses for 2 seconds.  If you press F8 at this
point, DOS displays...

MS-DOS will prompt you to confirm each CONFIG.SYS command.

...and then prompts with...

(command) [Y,N]?

...before executing each command.  Press Y to execute it or N to skip it.
After the last command in CONFIG.SYS, DOS prompts with...


...and you can skip AUTOEXEC.BAT by pressing Y.

Note: With DOS 6.2+, if you start with Ctrl+F8, you will be prompted
for action on each command in AUTOEXEC.BAT as well as CONFIG.SYS.

This step-by-step batch processing can also be used with any
batch file using the new COMMAND.COM syntax:

Command /Y /C myBat.Bat

  Skipping individual commands  
You can place a question mark (?) after any CONFIG.SYS command to force
DOS to verify whether you want to execute the command.  For instance...


...will cause DOS to display...


...and you can press Y to execute it or N to skip it.

See Also: Clean Boot
SWITCHES= (/N disables Clean Boot; /F skips the 2-second delay)
- -

Interactive Boot