Article ID: 75634 - View products that this article applies to.
This article was previously published under Q75634
Using a percent sign (%) in a batch file requires that two percent signs (%%) be specified.
For example, the command to display "5%" from a batch file would be :
MS-DOS uses %1, %2, ... %9 as replaceable command line parameters. For example, before executing the command ECHO %1, %1 will be replaced with the first parameter passed to the batch file. %0 is replaced with the command used to execute the batch file.
A single percent sign on a line is treated as a "nul" character in a batch file. For example:
If a command contains two percent signs, MS-DOS will treat any characters between them as an environment variable to be expanded. For example, if the SET command shows that the current environment variables are
ECHO % is processed as ECHO ECHO a%b is processed as ECHO ab
COMSPEC=C:\COMMAND.COM PATH=C:\DOS PROMPT=$P$G B=C
If there are no characters between the two percent signs, one percent sign is stripped off and the other will remain. This is why a FOR command that echos the name of each file with a .COM extension would be
ECHO %PATH% is processed as ECHO C:\DOS ECHO a%b% is processed as ECHO aC ECHO a%b b%a is processed as ECHO aa
but if the same command is placed in a batch file, the following is required:
FOR %V IN (*.COM) DO ECHO %V
FOR %%V IN (*.COM) DO ECHO %%V
"Microsoft MS-DOS Batch File Quick Reference," Microsoft Press.
Article ID: 75634 - Last Review: May 10, 2003 - Revision: 2.0
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