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Inspired while writing my other question (which i now deleted) (sometimes talking to the duck does help) I think I found a solution to my problem but I don't know how to do it.

I have the following command in a batch script

FOR /R %1 %%G IN (*) DO rdiff.exe signature "%%G" | 7za.exe a -mx0 -si"%%G" signatures.7z

What I would like to do is remove the text of %1 from %%G in the 7zip -si argument but leave it in the rdiff argument.

How would I go about doing that?

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up vote 2 down vote accepted

String manipulation is very awkward in the command prompt. Removing the contents of %1 from the beginning of %G would involve counting the characters of %1 (loop through the characters and increase a counter by one) and then use the substring syntax (%var:~start,length%).

Using forfiles should be much simpler, since it has a built-in command variable to access the relative path of the file (@relpath).

This should work:

forfiles /S /P %1 /C "cmd /V:on /C if @isdir==FALSE set R=@relpath&set R=!R:~3,-1!&%~dp0rdiff signature @path | %~dp07za a -mx0 -si\"!R!\" %~dp0signatures.7z"


  • /S makes forfiles recursive.

  • /P %1 specifies the path.

  • /C "cmd /V:on /C ... executes ... in a subshell with delayed variable expansion (!var! syntax).

  • if @isdir==FALSE checks for the presence of a file (rather than a directory).

  • set R=@relpath stores the relative path in a variable called R.

  • set R=!R:~3,-1! removes the string at the beginning "\." and the trailing double-quote.

  • %~dp0 forfiles changes directories to execute the command, specifying %~dp0 gives you the absolute path the batch file was run from.

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That looks good, but its no longer seeing rdiff.exe in the same folder as the batch file. if I do E:\rdiff>makeSig.bat E:\example it gives me the error message 'rdiff.exe' is not recognized as an internal or external command, operable program or batch file. – Scott Chamberlain Mar 15 '13 at 19:15
Forfiles seems to change directories to execute the command. That means the executables, the signatures file and the archive will require full paths. – Dennis Mar 15 '13 at 19:18
By the way, all the variable juggling doesn't seem to be necessary. Just using -si\@relpath should work as well. – Dennis Mar 15 '13 at 19:20
replacing the file-names of the programs to %~dp0rdiff.exe and %~dp07za solved it. I also needed to add to the name of the zip to make %~dp0signatures.7z – Scott Chamberlain Mar 15 '13 at 19:22
Also if I just use -si\@relpath I get blank directory and a directory named . in the zip file. but the string replacement works great. – Scott Chamberlain Mar 15 '13 at 19:26

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