The description below is from the book DOS the Easy Way by Everett Murdock Ph.D.
CLICK HERE for information about downloading the book.
Type: Internal (1.0 and later)
Purpose: Provides a way to insert remarks (that will not be acted
into a batch file.
During execution of a batch file, DOS will display (but not act on)
which are entered on the line after the REM command.
You cannot use separators in the comment except the space, tab, and
keep DOS from interpreting commands in a comment line, enclose the
For more information on the REM command, refer to Chapter 6, Tips for
comment - Any text up to 127 characters.
To add a comment to a batch file, enter
REM This is a comment line
To add a line to a batch file and to keep it from being displayed when
file is run, you must first turn the ECHO feature off. To keep the REM
line from being displayed, enter
rem This comment line will not be displayed