I find %~dp0
very useful, and I use it a lot to make my batch files more portable.
But the label itself seems very cryptic to me... What is the ~
doing? Does dp
mean drive and path? Does the 0
refer to %0
, the path to the batch file that includes the file name?
Or it is just a weird label?
I'd also like to know if it is a documented feature, or something prone to be deprecated.
This question is related to
batch-file
An example would be nice - here's a trivial one
for %I in (*.*) do @echo %~xI
it lists only the EXTENSIONS of each file in current folder
for more useful variable combinations (also listed in previous response) from the CMD prompt execute: HELP FOR
which contains this snippet
The modifiers can be combined to get compound results:
%~dpI - expands %I to a drive letter and path only
%~nxI - expands %I to a file name and extension only
%~fsI - expands %I to a full path name with short names only
%~dp$PATH:I - searches the directories listed in the PATH
environment variable for %I and expands to the
drive letter and path of the first one found.
%~ftzaI - expands %I to a DIR like output line
%~dp0 expands to current directory path of the running batch file.
To get clear understanding, let's create a batch file in a directory.
C:\script\test.bat
with contents:
@echo off
echo %~dp0
When you run it from command prompt, you will see this result:
C:\script\
(First, I'd like to recommend this useful reference site for batch: http://ss64.com/nt/)
Then just another useful explanation: http://htipe.wordpress.com/2008/10/09/the-dp0-variable/
The %~dp0 Variable
The
%~dp0
(that’s a zero) variable when referenced within a Windows batch file will expand to the drive letter and path of that batch file.The variables
%0-%9
refer to the command line parameters of the batch file.%1-%9
refer to command line arguments after the batch file name.%0
refers to the batch file itself.If you follow the percent character (
%
) with a tilde character (~
), you can insert a modifier(s) before the parameter number to alter the way the variable is expanded. Thed
modifier expands to the drive letter and thep
modifier expands to the path of the parameter.Example: Let’s say you have a directory on
C:
calledbat_files
, and in that directory is a file calledexample.bat
. In this case,%~dp0
(combining thed
andp
modifiers) will expand toC:\bat_files\
.Check out this Microsoft article for a full explanation.
Also, check out this forum thread.
And a more clear reference from here:
%CmdCmdLine%
will return the entire command line as passed to CMD.EXE
%*
will return the remainder of the command line starting at the first command line argument (in Windows NT 4, %* also includes all leading spaces)
%~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
Just found some good reference for the mysterious ~
tilde operator.
The %~
string is called percent tilde operator. You can find it in situations like: %~0
.
The :~
string is called colon tilde operator. You can find it like %SOME_VAR:~0,-1%
.
%1-%9
refer to the command line args. If they are not valid path values, %~dp1
- %~dp9
will all expand to the same value as %~dp0
. But if they are valid path values, they will expand to their own driver/path value.
For example: (batch.bat)
@echo off
@echo ~dp0= %~dp0
@echo ~dp1= %~dp1
@echo ~dp2= %~dp2
@echo on
Run 1:
D:\Workbench>batch arg1 arg2
~dp0= D:\Workbench\
~dp1= D:\Workbench\
~dp2= D:\Workbench\
Run 2:
D:\Workbench>batch c:\123\a.exe e:\abc\b.exe
~dp0= D:\Workbench\
~dp1= c:\123\
~dp2= e:\abc\
Great example from Strawberry Perl's portable shell launcher:
set drive=%~dp0
set drivep=%drive%
if #%drive:~-1%# == #\# set drivep=%drive:~0,-1%
set PATH=%drivep%\perl\site\bin;%drivep%\perl\bin;%drivep%\c\bin;%PATH%
not sure what the negative 1's doing there myself, but it works a treat!
The variable %0
in a batch script is set to the name of the executing batch file.
The ~dp
special syntax between the %
and the 0
basically says to expand the variable %0
to show the drive letter and path, which gives you the current directory containing the batch file!
Help = Link
Another tip that would help a lot is that to set the current directory to a different drive one would have to use %~d0
first, then cd %~dp0
. This will change the directory to the batch file's drive, then change to its folder.
Alternatively, for #oneLinerLovers, as @Omni pointed out in the comments cd /d %~dp0
will change both the drive and directory :)
Hope this helps someone.
Source: Stackoverflow.com