I have been using Cygwin 32-bit on Windows 7 Professional 64-bit. I had the HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\kernel\ObCaseInsensitive registry key set and all has been good: I could get true case-sensitive filename handling, I could create FOO.txt and foo.txt in the same directory.

Now that Cygwin 64-bit is released, I want to try it on Windows 7 Professional 64-bit. It turns out that the ObCaseInsensitive registry key has no effect for Cygwin 64-bit because the key seems to be for the Win32 subsystem only. Subsystem for UNIX-based Applications (SUA) is also not available in Windows 7 Professional 64-bit (Enterprise or Ultimate is required). In fact, I don't even know if having SUA installed would help at all.

Does anybody know if it is possible to get case-sensitive filename handling with Cygwin 64-bit on Windows 7 Professional 64-bit?

2 Answers 2


Case sensitivity does work on x86_64-cygwin. Remember that on 64-bit Windows systems, there are effectively two registries, one for 32-bit processes and another for 64-bit processes. (In Cygwin, these are represented by /proc/registry32 and /proc/registry64.) Setting the key again with regtool -w and rebooting should fix this for you.

  • 1
    Mea culpa. Further tests confirm that the ObCaseInsensitive key does have an effect on Cygwin 64-bit: I could echo 'FOO' > FOO.txt; echo 'bar' > foo.txt and create two different files. The problem seems to be with git. git in Cygwin 64-bit doesn't seem to be patched to have correct case-sensitive filename handling, despite the ObCaseInsensitive registry key having been set.
    – Kal
    Aug 16, 2013 at 1:46

You could define a function that checks the case of the target directory (without having to change the Windows Registry). This way, I have in ~/.bash_functions file the following code:

unset cd_func2 2> /dev/null
unalias cd 2> /dev/null
cd_func2 () {

    echo $1 | grep -q '^/' && cd $1 && return 0
    for f in `echo $1 | sed -e 's/\// /g'` ; do
        _NEW_PATH=$(ls -a | grep -i ^"$f"$)
        [ "$_NEW_PATH" ] && cd $_NEW_PATH && continue
        echo "Directori inexistent $f" && return 1

alias cd=cd_func2

EDIT: More general parameter handling.

Hope it helps.

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