Using if to verify the presence of a file
The following message appears if Windows 2000 cannot find the file Product.dat:
if not exist product.dat echo Can't find data file
Using if to post a message when an error occurs
The following example displays an error message if an error occurs during formatting of the disk in drive A:
:begin
@echo off
format a: /s
if not errorlevel 1 goto end
echo An error occurred during formatting.
:end
echo End of batch program.
If no error occurs, the error message is skipped.
Using if to verify the presence of a directory
The following example tests for the existence of a directory. The if command cannot be used to test directly for a directory, but the null (NUL) device does exist in every directory. Therefore, you can test for the null device to determine whether a directory exists.
if exist c:mydir\nul goto process
Using the else clause
The else clause must occur on the same line as the command after the if. For example:
IF EXIST filename. (
del filename.
) ELSE (
echo filename. missing.
)
The following does not work, because the del command must be terminated by a newline:
IF EXIST filename. del filename. ELSE echo filename. missing
The following does not work, because the else command must be on the same line as the end of the if command:
IF EXIST filename. del filename.
ELSE echo filename. missing
The following form of the original statement works, if you want to format it all on a single line:
IF EXIST filename. (del filename.) ELSE echo filename. missing