SETLOCAL ENABLEEXTENSIONSwithin your NT shell scripts (batch files) or execute those scripts using
SETLOCALpage if you intend to use
Batch files can only handle parameters %0 to %9
%0 is the program name as it was called,
%1 is the first command line parameter,
%2 is the second command line parameter,
and so on till
OK, tell me something new.
%0 is the program name as it was called, in DOS
%0 will be empty for AUTOEXEC.BAT if started at boot time.
This means that, in AUTOEXEC.BAT, you can check if it is being started at boot time or from the command line, for example to prevent loading TSR's twice.
The batch file's limitation to handle parameters up to
%9 only can be overcome by using SHIFT.
Let us assume your batchfile is called with the command line parameters
A B C D E F G H I J K.
%1 equals A,
%2 equals B, etcetera, until
%9, which equals I.
%10 does not equal J but A0;
%10 is interpreted as
%1, immediately followed by a 0.
Does that mean the rest of the parameters is lost? Of course not. After your batch file handled its first parameter(s) it could
SHIFT them (just insert a line with only the command
SHIFT), resulting in
%1 getting the value B,
%2 getting the value C, etcetera, till
%9, which now gets the value J.
Continue this process until at least
%9 is empty.
Use a loop to handle any number of command line parameters:
@ECHO OFF :Loop IF "%1"=="" GOTO Continue • • Here your batch file handles %1 • SHIFT GOTO Loop :Continue
In that case, use
In Windows NT 4, 2000 and XP you can
SHIFT the command line parameters starting from the nth positions using
/n switch, where
n can be any (integer) number between 0 and 8:
SHIFT /4 will leave
%3 untouched, and shift
To use this feature, Command Extensions should be enabled.
An easy work-around in NT 4 and later is:
FOR %%A IN (%*) DO ( • • Now your batch file handles %%A instead of %1 • )
No need to use SHIFT anymore.
Some characters in the command line are ignored by batch files, depending on the DOS version, whether they are "escaped" or not, and often depending on their location in the command line:
I know of several occasions where these seemingly useless "features" proved very handy.
Keep in mind, though, that these "features" may vary with the operating systems used.
More on command line parsing can be found on the PATH and FOR (especially FOR's interactive examples) pages.
Windows NT 4 introduced a set of new features for command line parameters:
|%CmdCmdLine%||will return the entire command line as passed to
|%*||will return the remainder of the command line starting at the first command line argument (in Windows NT 4,
|%~dn||will return the drive letter of %n (n can range from 0 to 9) if %n is a valid path or file name (no UNC)|
|%~pn||will return the directory of %n if %n is a valid path or file name (no UNC)|
|%~nn||will return the file name only of %n if %n is a valid file name|
|%~xn||will return the file extension only of %n if %n is a valid file name|
|%~fn||will return the fully qualified path of %n if %n is a valid file name or directory|
Windows 2000 and XP add even more options.
More information can be found at the page explaining NT's CALL command.
To remove the leading space of %* included by NT 4 use the following commands:
SET commandline=%* IF NOT CMDEXTVERSION 2 SET commandline=%commandline:~1%
|Note:||Please read the Best Practices section on command line input validation|
A tip by Oliver Schneider:
@ECHO OFF GOTO:%~1 2>NUL ECHO Invalid argument: %1 ECHO. ECHO Usage: %~n0 number ECHO. ECHO Where: number may be 1, 2 or 3 only GOTO:EOF :1 :2 :3 REM Code to do something with the validated argument starts here • • REM End of batch file
|Note:||This tip dates back to way before the Windows NT era.
In CMD.EXE (Windows NT 4 and later), a batch file exits if an invalid label is specified, unless the next line tests for ERRORLEVEL 1.
@ECHO OFF GOTO:%~1 2>NUL IF ERRORLEVEL 1 ( ECHO Invalid argument: %1 ECHO. ECHO Usage: %~n0 number ECHO. ECHO Where: number may be 1, 2 or 3 only GOTO:EOF ) :1 :2 :3 REM Code to do something with the validated argument starts here • • REM End of batch file
For a limited number of allowed arguments, this is a time saving technique.
Do note, however, that labels are case sensitive, so you may not want to use this technique for "string type" arguments.
Also keep in mind that labels cannot contain delimiters (space, comma, semi-colon, etcetera), they must be unique, and that only the first 8 characters are used (so the first 8 characters must be unique!).
This technique is best used when each valid value for %1 has its own batch code to process it:
@ECHO OFF GOTO:%~1 2>NUL IF ERRORLEVEL 1 ( ECHO Invalid argument: %1 ECHO. ECHO Usage: %~n0 number ECHO. ECHO Where: number may be 1, 2 or 3 only GOTO:EOF ) :1 REM Preprocess value 1 • • GOTO Common :2 REM Preprocess value 2 • • GOTO Common :3 REM Preprocess value 3 • • :Common REM Common processing of preprocessed values • • REM End of batch file
|Note:||Note the extra
It is required to make the code work in Windows 7 and 8 too.
|page last uploaded: 7 October 2014, 11:59|