Parameters

A parameter (or argument) is any value passed into a batch script:

C:> MyScript.cmd January 1234 "Some value"

Parameters may also be passed to a subroutine with CALL:

CALL :my_sub 2468

You can get the value of any parameter using a % followed by it's numerical position on the command line. The first item passed is always %1 the second item is always %2 and so on

%* in a batch script refers to all the arguments (e.g. %1 %2 %3 %4 %5 ...%255)

Parameter Extensions

When a parameter is used to supply a filename then the following extended syntax can be applied:

we are using the variable %1 (but this works for any parameter)

%~f1 Expand %1 to a Fully qualified path name - C:utilsMyFile.txt

%~d1 Expand %1 to a Drive letter only - C:

%~p1 Expand %1 to a Path only e.g. utils this includes a trailing which may be interpreted as an escape character by some commands.

%~n1 Expand %1 to a file Name, or if only a path is present (with no trailing backslash) - the last folder in that path

%~x1 Expand %1 to a file eXtension only - .txt

%~s1 Change the meaning of f, n and x to reference the Short name (see note below)

%~1 Expand %1 removing any surrounding quotes (")

%~a1 Display the file attributes of %1

%~t1 Display the date/time of %1

%~z1 Display the file size of %1

%~$PATH:1 Search the PATH environment variable and expand %1 to the fully qualified name of the first match found.

The modifiers above can be combined:

%~dp1 Expand %1 to a drive letter and path only

%~nx2 Expand %2 to a file name and extension only

When writing batch scripts it's a good idea to store these values in a variable SET _LogFile=%~dp1, the rest of the script can then refer to the easy-to-read variable name %_LogFile% This will also make life easier if you later need to change around the order of the parameters.

Passing by Reference

In addition to passing numeric or string values on the command line, it is also possible to pass a variable name and then use the variable to transfer data between scripts or subroutines. Passing by reference is a slightly more advanced technique but can be particularly useful when the string contains characters that are CMD delimiters or quotes.

Links relative to the Batch Script

You can get the pathname of the batch script itself with %0, parameter extensions can be applied to this so %~dp0 will return the Drive and Path to the batch script e.g. W:scripts and %~f0 will return the full pathname W:scriptsmybatch.cmd

You can refer to other files in the same folder as the batch script by using this syntax:

  CALL %0..SecondBatch.cmd

This can even be used in a subroutine, Echo %0 will give the call label but, echo "%~nx0" will give you the filename of the batch script.

When the %0 variable is expanded, the result is enclosed in quotation marks.

Bug when using ~s for short file/folder names

There is a bug involving the ~s option, the displayed output may be wrong if the current directory name is not the same as the short (8.3) name of the directory.
A workaround is to run command.com /c rem which will change the current directory to 8.3, details here.

Use %~a1 to display the Extended Attributes of a file.

FOR's %%~aI recognizes 9 NTFS file attributes. The expansion of a file attribute produces a series of 9 dashes, with each recognized attribute replacing a dash with a letter. A file with no recognized attributes or with none set will expand to 9 dashes like this: ---------

 Attribute                    Expansion 
 FILE_ATTRIBUTE_DIRECTORY     d-------- 
 FILE_ATTRIBUTE_READONLY      -r------- 
 FILE_ATTRIBUTE_ARCHIVE       --a------ 
 FILE_ATTRIBUTE_HIDDEN        ---h----- 
 FILE_ATTRIBUTE_SYSTEM        ----s---- 
 FILE_ATTRIBUTE_COMPRESSED    -----c--- 
 FILE_ATTRIBUTE_OFFLINE       ------o-- 
 FILE_ATTRIBUTE_TEMPORARY 	   -------t- 
 FILE_ATTRIBUTE_REPARSE_POINT --------l
 FILE_ATTRIBUTE_NORMAL        ---------

Other NTFS attributes not recognised by %%~aI can be read using FSUTIL usn command:
FILE_ATTRIBUTE_ENCRYPTED
FILE_ATTRIBUTE_NOT_CONTENT_INDEXED
FILE_ATTRIBUTE_SPARSE_FILE

Example: Expansion of a file with the Hidden and System attributes:
---hs----

FOR parameters

The FOR command creates parameter variables which are identified with a letter rather than a number (e.g. %%G).
The Parameter Expansions described above can also be applied to these.
To avoid confusion between the two sets of letters you may wish to avoid using the letters (a, d, f, n, p, s, t, x, z) as FOR parameters or just choose a FOR parameter letter thats UPPER case.
So for example in a reference like %%~fG the %%G is the FOR parameter, and the ~f is the Parameter Expansion.

Examples:

Pass parameters from one batch to another:

   MyBatch.cmd SMITH 100

Or as part of a CALL :

   CALL MyBatch.cmd SMITH 100

Passing values from one part of a script to another:

   :: Using CALL to jump to a subroutine
   CALL :s_staff SMITH 100

   :: Calling a subroutine from a FOR command
   FOR /F %%G IN ('DIR /b *.*') DO call :s_subroutine %%G

“A gift is pure when it is given from the heart to the right person at the right time and at the right place, and when we expect nothing in return” ~ The Bhagavad Gita