Batch parameter %~s1 gives incorrect 8.3 short name

Question

I\'m trying to write a batch file in Windows XP that takes in a fully-qualified path name and outputs the 8.3 short name version...

@echo off
echo \"%~s1\"
<         


        

Answer 1

It's not a bug in your code, it's a bug of XP!
With Vista the same code works.

It looks like a sort of a buffer corruption.
It depends of the length of the last directory name, the last characters are copied to the "short name".

And it only occurs if in the filename is one or more characters out of [];,+=<space>

A short test case

@echo off
setlocal EnableDelayedExpansion
set myDir=
set myFile=a[1].bat
set map=123456789ABCDEFGHIJKLMNOPQRSTUVW

for /L %%n in (0 1 26) do (
  set "myDir=!myDir!!map:~%%n,1!"
  md !myDir!
  echo dummy > "!myDir!\!myFile!"
  echo Dir=!myDir!
  for %%X in ("!myDir!\!myFile!") do echo   %%~sX
  echo(
  del "!myDir!\!myFile!" > nul
  rd !myDir!
)

The results of the last lines

Dir=123456789A
  C:\Projekte\batch\123456~1\A_1_~1.BAT

Dir=123456789AB
  C:\Projekte\batch\123456~1\A_1_~1.BATt

Dir=123456789ABC
  C:\Projekte\batch\123456~1\A_1_~1.BATat

Dir=123456789ABCD
  C:\Projekte\batch\123456~1\A_1_~1.BATbat

Dir=123456789ABCDE
  C:\Projekte\batch\123456~1\A_1_~1.BAT.bat

Dir=123456789ABCDEF
  C:\Projekte\batch\123456~1\A_1_~1.BAT].bat

Dir=123456789ABCDEFG
  C:\Projekte\batch\123456~1\A_1_~1.BAT1].bat

Dir=123456789ABCDEFGH
  C:\Projekte\batch\123456~1\A_1_~1.BAT[1].bat

Dir=123456789ABCDEFGHI
  C:\Projekte\batch\123456~1\A_1_~1.BATa[1].bat

Dir=123456789ABCDEFGHIJ
  C:\Projekte\batch\123456~1\A_1_~1.BAT\a[1].bat

Dir=123456789ABCDEFGHIJK
  C:\Projekte\batch\123456~1\A_1_~1.BATK\a[1].bat

Dir=123456789ABCDEFGHIJKL
  C:\Projekte\batch\123456~1\A_1_~1.BATKL\a[1].bat

Dir=123456789ABCDEFGHIJKLM
  C:\Projekte\batch\123456~1\A_1_~1.BATKLM\a[1].bat

Dir=123456789ABCDEFGHIJKLMN
  C:\Projekte\batch\123456~1\A_1_~1.BATKLMN\a[1].bat

Dir=123456789ABCDEFGHIJKLMNO
  C:\Projekte\batch\123456~1\A_1_~1.BATKLMNO\a[1].bat

Dir=123456789ABCDEFGHIJKLMNOP
  C:\Projekte\batch\123456~1\A_1_~1.BATKLMNOP\a[1].bat

Dir=123456789ABCDEFGHIJKLMNOPQ
  C:\Projekte\batch\123456~1\A_1_~1.BATKLMNOPQ\a[1].bat

Dir=123456789ABCDEFGHIJKLMNOPQR
  C:\Projekte\batch\123456~1\A_1_~1.BATKLMNOPQR\a[1].bat